Talk:High dynamic range imaging/Archive 1

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Archive 1 Archive 2


Also, the examples provided in the article are quite poor. There is a tendency for newbies to this technique to overdo it. Agateller 15:52, 7 August 2006 (UTC)

I've just gone through and removed most overt references to photography, as well as the gallery at the end. I've also tried to explain where HDR images come frome (i.e rendering or from multiple exposures) and an intro to tone mapping.
Unfortunately, you're falling into the same trap as the others. HDR(I) is not a photographic method. What you're describing is merging of two or more exposures, and I think photographers have been doing that with film/paper long before digital photography came along.
HDR is simply about storing images in such a way as to allow a very large range of values to be stored, and for those values to represent real-world measurements instead of simply how bright a pixel should be on a monitor. Those pixel values can be produced from combining photos or they can be computed using some rendering algorithm. But here's the important part - those "HDR photos" are not HDR. The intermediate may have been, in which case they've been run through a horrible tone mapping algorithm trying to show too much dynamic range. But the photos we are looking at are not HDR.
--Imroy 17:16, 7 August 2006 (UTC)
The only utility to HDR is to compensate for limited dynamic range in image capture, which is really only a problem in photographic systems. It's just another TLA for something that has been around for ages. Sometimes geeks latch onto something that has been around for ages and then like to pretend that they've invented it themselves by giving it a name. Agateller 07:41, 8 August 2006 (UTC)
You're missing my point. Let me put it in bold: HDR is not necessarily about photography. Yes, there is a fad at the moment involving combining several photos, and they call it "HDR". But HDR(I) has been around since the mid-to-late 80's and has other applications. I'm also annoyed at all these horrible photos being labelled "HDR", but I'm not blaiming HDR. --Imroy 15:59, 8 August 2006 (UTC)
I'm all for historical accuracy, but we also have to be relevant today. Today, the term HDR is increasingly being applied differently. I claim that a large number, perhaps even a majority, of people today are looking for more information on the concept of taking multiple exposures in digital photographs for the purpose of bringing out a higher range of color. I think the revisions of this article after 15:49, 7 August 2006 fail to be effective for people who are looking for more information on that concept. I'm proposing, in an effort to be effective for more people, to have portions of old content (including the older photo of the church) moved into an article titled "High dynamic range (digital?) photography," with each article referencing each other appropriately.
The term "HDR" as it is used by many is actually a sub-set of HDR(I). For example, even though most people use digital point-and-shoot cameras nowadays, and refer to "taking photos" in everyday speech, the photography article deals with the history of photography and the full range of the art. Similarly, using Photoshop or any other package to "make a HDR" is just an application of HDR and this article should not restrict itself to the narrow definition that's come into recent use. While I accept that language is alive and changes, most people aren't experts, and they also use shortened or abbreviated terms in common usage. I have no problem of (re-)adding those sorts of photos into the article, as long as it is made clear that they are simply one application of HDR. Before my edits, the article (as I interpreted it) appeared to imply that those photos were HDR and that was it. A few (notably Zimberoff, see below) seemed convinced that HDR was only about photos and could be achieved by simply merging different exposures. Hopefully my edits and example images demonstrate that HDR images aren't just about photos and can be used for more interesting things (e.g lightprobes). --Imroy 07:46, 26 August 2006 (UTC)
Furthermore, most HDR introductions state Paul Debevec to be the pioneer on these methods for digitally combining different exposed images into one HDR image. However, he is not. Steve Mann (cited by Debevec) indeed did so first in 1994 digitally and cites Charles Wyckoff's publications on the same topic from 1961 and 1962 for chemical films. I could not find earlier publications on this topic.

Actually the first to introduce the concept of taking digital images at different exposures and combining them to a single image with HDR are a group from the Technion in Israel led by Y.Y.Zeevi. first patent on the concept was published in Israel in 1988 "Wide Dynamic Range Camera (Y.Y. Zeevi, R. Ginosar and O. Hilsenrath), Israel, 1988, Worldwide 1989, U.S.A. Patent No. 5,144,442, 1992." In 1993 first commercial medical camera was introduced that performed real time capturing of multiple images with different exposures, and produced an HDR video image.

Now, at 2009 the HDR Video or Wide Dynamic Range mode for video cameras is de-facto standard in the surveillance camera industry. There are sensors that support multiple exposures at real time, and cameras that produce HDR Video any remarks befor adding this info to the main article?--Noso —Preceding unsigned comment added by (talk) 19:11, August 30, 2007 (UTC)


I'm not sure I see the application for HDR. (I've had a look at HDRShop but wasn't much wiser.) Is it used to expand the dynamic range for print? I presume that typical PC displays would not show a high dynamic range. -DRB

A: No, LCD or CRT displays can not show HDR, but at least experimental HDR displays are already available (see this [link]). Photographers take HDR photographs of difficult scenes (like landscapes with huge luminance range), which they later manipulate in Photoshop using contrast, brightness, dodging and burning tools, to make them suitable for print. Tone mapping algorithms are supposed to do the same thing automatically.

HDR image formats are just an application of the general principal that you should keep information as long as possible. It's very easy to generate images with enormous dynamic range (especially with artificial rendering); a HDR output format allows you to keep an exact representation such an image for later post-processing. This is different from traditional image formats, which are optimized for the limitations of display devices, and can't represent many images exactly -- e.g. if you discover after your 5 day ray-trace is done that you misjudged the lighting, you can edit a HDR output image to adjust it, without losing anything, but if you used a more limited output format, you may have to simply redo the rendering. HDR images also make it much more practical to do post-processing of images.

HDRI images are used extensively in 3d modeling as they can be used as realistic light sources. This is especially important when integrating CG effects into live action cinema as the CG model can be lit by the real scene rather than resorting to modeling the scene with approximation of the main light sources. As mentioned below its is also being introduced into gaming.--Pypex 23:39, 9 November 2005 (UTC)
I'm involved in the design, development and production of realtime HDR automotive video systems, which are capable of generating HDR images at typically about thirty frames per second. This is an important application space, as it provides a vehicle user / vehicle machine vision processor with significantly more scene content information upon which they can act. PD (talk) 15:31, 29 February 2008 (UTC)

Merge "High dynamic range rendering" to this article

It seems both articles have an almost similar title but different contents. Given High dynamic range imaging refers to broader range of fields, I found it would be more appropriate to merge contents from High dynamic range rendering to this page. Comments? ╫ 25 ring-a-ding 19:51, 1 October 2005 (UTC) ╫

Yeah, they should probably be merged. Thunderbrand 13:16, 6 October 2005 (UTC)
I for once agree with the merge, the HDRR is rather incoherently written IMHO, and HDRI is by far the more important aspect of the subject.--Pypex 23:44, 9 November 2005 (UTC)
OPPOSE: I am pretty sure that high dynamic range imaging and high dynamic range rendering are different; mostly related to the differences in ray-tracing and real-time polygonal rendering.
HDRI is a non-real time render of HDR, while HDRR is a real time render. But I think the objectives between HDRI and HDRR are different. HDRI attempts to preserve and record lighting data from photographs using say another 32-bits for lighting information from different exposures of the camera (since we don't really have an HDR camera). HDRR attempts to simulate the highs and lows of any particular scene by adjusting the brightness of any given object by the monitor's brightness capabilities. Lighting information isn't exactly accurate with the 24-bit color model used today, since there's only 256 shades of any given color, meaning the contrast ratio is stuck at 256:1. Both HDRI and HDRR technically should benefit from an HDR display though. Given this case, I think it's appropriate to say that HDRI is a photography related subject while HDRR is a computer graphic related subject.
OPPOSE: It seems to be clear HDR itself contains, or includes, both HDR imaging (HDRI) and HDR rendering (HDRR). Even though they are related, imaging is about caputring, processing, viewing and printing of HDR, while HDRR is focusses on rendering virtual scenes by using more than 8 bits of color definition. The goals are very different, only the means are similar, and so also the content is very different.
But there is at least two elements which needed fixing: The HDRI article talksed for a bit more than a whole paragraph about HDRR. This detracts because it belongs to HDRR. HDRR should be seen as a specialized sub-article of HDR or HDRI. I moved these to HDRR and added a short explanation to the link to the HDR rendering article.
Clearly, don't merge, but specialize. Eventually, a common parent article on HDRI and HDRR named just HDR may be created to which topics which might concern both HDR photo imaging and virtual scene rendering, which is the basic explanation of highy dynamic range and a deeper discussion about displaying a higher dynamic range. I think this is the ultimate way to go, because both articles will grow over time and things need to be carefully placed then: Common things on a common place, different things in different articles.
Lastly, the Link list of this article needs to be cleanup or better, structuring of the external links list. It was a huge linear list without any classification, so it looked at this link list and the one at High dynamic range rendering, and removed double links, but still, two links need to be reviewed and categoried or deleted --NoSoftwarePatents 07:46, 20 January 2006 (UTC)
"...the 24-bit color model used today, since there's only 256 shades of any given color, meaning the contrast ratio is stuck at 256:1." Yikes. The number of bits has nothing to do with the dynamic range / contrast ratio. A one bit per color channel image could represent a dynamic range of 1 million to 1, or 20 EV. It would just (obviously) completely lack precision between brightness levels.
A parent HDR article over HDRI and HDRR would also need to cover things like HDR audio. HDRR is clearly a subset of HDRI. Darxus (talk) 00:27, 19 August 2009 (UTC)

Link removal

Is it ok to have 3 external links in this article versus around 46 in some older versions?-- (talk) 04:38, 29 February 2008 (UTC)

Perhaps, though zero might be even better. Dicklyon (talk) 05:26, 29 February 2008 (UTC)
Some older version of this article made me interested in HDR and actually had enough information to get started. I don't see how present version can do that. Just a lot of general wording and some fairly bad photographs. (talk) 20:24, 29 February 2008 (UTC)

I have removed the cambridgeincolour link because the owner of that site has sought to imbed lots of advertising all through the tutorial. Forsh (talk) 10:12, 27 January 2008 (UTC)

I'm removing a few of the external links at the end of this article. In case anyone wants to resurect any, here are the links with my notes.

I also gave a name to I remember finding it myself a while ago and it is reasonably informative.

Imroy 16:43, 3 March 2006 (UTC)

Im wondering why this link get removed all the time: High Dynamic Range Photography, specific information about HDR photography, from shooting to post processing
Its about a month ago that i put it in and now its getting removed. The information found there helped me get started with HDR and also its the only site i have found clearly explaining about movement in HDR and why its destructive.

This link is apparently okay: ... that i do not understand, this page actually do not bring anything new to the table.
Musicanselr (talk) 14:40, 4 May 2008 (UTC)

I agree it does "not bring anything new to the table." And its an anonymous blog; the link is the only contribution of an anon editor; and it was added without comment. These all make it spam in my book. If someone wants to look it over and tell us why it's appropriate to add to external links, we can consider it. So far, nobody has done so. Dicklyon (talk) 17:05, 4 May 2008 (UTC)
Okay. That answers the second part of my "question", but what about the first part: High Dynamic Range Photography, why is it getting removed all the time? Because its not an anonymous blog ? Only reason i added it was because it helped me out, but im not gonna keep on adding it just to have it removed. No point in that. How are people going to look it over if it gets removed all the time ? Or are you saying i should add it a write a reason why im adding it? Musicanselr (talk) 17:14, 4 May 2008 (UTC)
The page you link to does not add anything new to the article. This Wikipedia article is not meant to be a tutorial on how to create HDR images and if you encounter problems with movements in the scene, a quick Google search for “HDR movement” will turn up the page you mentioned. So no point in adding it in the external links section. — Richie 21:18, 4 May 2008 (UTC)
Okay - point taken, but then i still think that needs to be removed. Agree? Musicanselr (talk) 08:51, 5 May 2008 (UTC)
It seems to me like a concise hands-on tutorial on how to actually do ‘HDR photography’. Seeing that it’s the only external link of that kind, I would keep it. — Richie 10:54, 5 May 2008 (UTC)
Well now its the only link of that kind :) and i still do not think it bring anything new. Musicanselr (talk) 12:18, 5 May 2008 (UTC)

Flickr HDR group?

I've just removed links to the Flickr "HDR" group for the third time. I'm just wondering what other people think of this external link (

My objection is that the photos presented are not actually HDR images. They're created from a set of bracketed exposures, apparently all with PhotoShop CS2, and then badly tone-mapped into JPEG's. Yes, a HDR image is produced at some point, but I've signed up for Flickr and still nowhere is there an option to download the photos in a HDR format.

On top of that, I really, really don't like the tone mapping used. For example, User:Deanpemberton's recent addition of Image:Old saint pauls 2.jpg. It's just so flat! Take the image into an editor like The GIMP and look at the histogram. It's centred around 50% and decreases out from there. That's not natural. Tone mapping was originally meant to simulate a photo-like "exposure" from a HDR render e.g Radiance. The tone mapping employed here is something else entirely. It's trying to compress the whole dynamic range of an image into an LDR JPEG. The result is flat and almost cartoon-like.

I guess what I'm trying to explain is that the Flickr group does not represent HDR imaging, and perhaps even leads to a misunderstanding of that "HDR" means. This can already be seen over at High dynamic range rendering, which appears to be mostly written by gamers. To many there, "HDR" involves blooming or other effects that can be faked without HDR. Please don't mislead any more people about what HDR is. Imroy 02:48, 23 March 2006 (UTC)

So what is HDR?

I think you're right in general that the flickr HDR group is misleading about what HDR is, but I disagree with the two reasons you gave.

Except for just a couple of very expensive pro cameras, taking bracketed exposures *is* currently the way to capture HDR images! Debevec published _the_ paper on how to do this.

As far as tone mapping goes, I fail to see why bad tone mapping makes something not HDR. The images on flickr are HDR images with mostly bad tone mapping. I don't mind keeping the flickr link off this page- it's certainly not defining or leading HDR development in any way. But you might want to consider using the flickr link as motivation for why people are actively researching tone mapping-- because it actually takes some effort and it's fairly easy to get it wrong even with Photoshop.

Maybe there should be a section of external links that show commodity application of different HDR techniques and approximations- flickr and Photoshop could certainly go there, along with Half Life and whatever other junk people want linked.

In general it would help to be clear about what HDR is, rather than asserting what it isn't. Both bracketed exposures and tone mapping have historically been an integral part of the subject of High Dynamic Range Imaging. If we divorce those things completely, all we're left with to talk about is "more than 8 bits per channel". Yay. —Preceding unsigned comment added by (talkcontribs)

OK, firstly - the *whole idea* of tone-mapping is to make something "not HDR". It's to convert from HDR to LDR for display. And if we're going to have tone-mapped images, I would prefer to show the effects of different algorithms on the same image - to show that the LDR images are just representations of the same HDR.
The problem with trying to show HDR is that no web browser (to my knowledge) can currently display HDR images. So we're forced to make LDR JPEG's that do display in web browsers. And I think this is where it gets tricky. I think instead of using a tone-mapping algorithm to compress a huge dynamic range into a flat, lifeless image, we should try to show that the HDR images have a wide range of light levels (dynamic range). One way is by showing mutliple exposures of the same image. But then if it's a photo, people will just say "you took different exposures, big deal!". We need some way of demonstrating that the HDR image has all of these "exposures" in one image, and why it's so useful.
Perhaps one way is with a rendering using a light probe, like Debevec's "rendering with natural light". Demonstrate (somehow) that the light probe (a HDR environment map) is actually lighting the scene, with no other sources of light. Or is that too technical? I know it's been used for several SFX shots in hollywood movies over the last few years. In fact, it's probably quite common now.
Another demonstration could show how various effects (e.g motion blur) are more realistic when done in a high-dynamic colour space. Any other ideas?
Imroy 00:12, 18 April 2006 (UTC)
> We need some way of demonstrating that the HDR image has all of these "exposures" in one image, and why it's so useful.
Well, yeah on the web we can show bracketed exposures before and bracketed exposures after, or we can show bracketed exposures before and a tone-mapped image after. For wikipedia's purposes it seems easier to motivate HDR for the lay-person using the latter, IMO. Also, you could always link to a java HDR viewer (such as But that's just interactive tone-mapping, so doesn't exactly solve your issue. But tone mapping is integral to HDR's history, and aside from that you don't need to have an actual elephant in the Wikipedia in order to write an article about one.
Tone mapping came before the HDR file format, and the original reason for inventing an HDR file format was to be able to apply different tone mappings without re-rendering, and to research different tone mapping techniques. You're right in a strict technical sense that tone-mapping is there to make something not HDR, but saying that doesn't exactly paint an accurate portrait of HDR techniques or the historical reasons for having them, IMO.
Your suggestion for demonstrating multiple tone mappings is a good one- either this article or the tone mapping one should do that. Motion blur is a worthy example as well, possibly most appropriate in the HDRR article...
Anyway, as far as your original question goes, don't worry too much about flickr, I think it's just fine to keep that link off this article. 20:32, 18 April 2006 (UTC)

Maybe a section in the article about possible "artistic abuses" of the HDR concept would solve the problem? It is true that the original purpose of HDR formats was to capture and represent a wide range of physically accurate radiative data. But the current trend in certain circles happens to be to use it as just another effect filter. There's not really a point in ignoring this development. It will be better to name it for what it is, mention a few notable(!) examples (possibly even by pointing to the Flickr group), and get over it. --Latebird 13:08, 25 April 2006 (UTC)

Photographic related links?

Is this article solely intended to be about HDRi in CG/Rendering environment or may it be designated to add information about photographic concerns with HDR and tone mapping? -- I would like to add as external link, beacuse it is a FAQ about HDR and photographic concerns. What du you think about this approach?

That link looks good. It's not trying to sell a product (that I can see) and provides some real infomation. Of course, it would be best if that sort of information could be incorporated in the Wikipedia article (don't violate WP:COPY), but I wouldn't have any problem with that link being added. Imroy 18:13, 11 April 2006 (UTC)
"It's not trying to sell a product" - and that "purchase" button on top of the page? If there are links to sites offering Photomatix and HDRShop I would like to see here also links to easyHDR website ( and FDRTools ( [not a Wikipedia editor] 30 July 2006
On March 30th I added an external link referring to the homepage of FDRTools. Imroy responded with:
"Please do not add commercial links (or links to your own private websites) to Wikipedia. Wikipedia is not a vehicle for advertising or a mere collection of external links. You are, however, encouraged to add content instead of links to the encyclopedia. See the welcome page to learn more. Thanks. Imroy 10:09, 30 March 2006 (UTC)"
I am heavily surprised to see now links to the homepage of Photomatix. May be Photomatix is now open source software without the need to pay some fee? FDRTools 15:33, 07 September 2006 (UTC)

Sensitometry 21:39, 4 June 2007 (UTC)

the example

shouldn't the heading state that those are tone mapped aswell?

— Preceding unsigned comment added by (talk) 09:43, 6 May 2006 (UTC)


This article needs more information on how these images are created. For example, does it require that you have all six shots, or can the effect be accomplished with fewer exposure samples? --DDG 21:37, 2 June 2006 (UTC)

two different subjects

there should be two articles, one for photoshop hdr/tonemapped image processing (taking several exposures and combining them into one image) and one for cg related hdr (using an hdr image dynamically for lighting, etc). they are related, but different enough to warrant seperating. 12:12, 21 June 2006 (UTC)

There are two such pages - See Dynamic range (disambiguation) 20:48, 4 June 2007 (UTC)

Photoshop may be a special case, more targeted at artistic uses. But other than that there's no inherent difference between photographic-composite and computed images. In fact, the two approaches are often combined. Composite images are used for environment mapping within computed images, and computed images are merged with composite images for presentation purposes (architectural mock-ups). As long as we're talking about scientifically "correct" uses, the method of creation is determined by practical requirements, not because there are different principles involved. --Latebird 16:52, 21 June 2006 (UTC)

Comment in article

It is inconceivable that any one person should be credited with pioneering the use of so-called "high dynamic range imaging." Images using this technique have been created by analog means for decades, quite easily at that, by means of a process called image "sandwiching." Sandwiching essentially achieves the same results as HDRI by, well, sandwiching and rephotographing several film transparencies captured at various exposures to combine the effects of various exposures on a new transparency. The final result is the new "original." It is supposed to more closely resemble how the brain perceives what the eyes actually see. The transposition of this technique to digital capture does not represent a new paradigm, any more so than do the techniques of electronically dodging or burning an image as compared to performing these techniques in the darkroom.--Zimberoff 00:48, 4 August 2006 (UTC)--Zimberoff 00:48, 4 August 2006 (UTC)

This was in the article. I'm removing it and pasting it here. -- 02:27, 4 August 2006 (UTC)


Seeing Zimberoff's misguided contribution being removed finally made me do something for this article. I rendered a simple scene, manipulated the image, uploaded them, and added them. I hope people find the images and text useful.

Now, for a while I've been meaning to rearrange this and a number of related articles. Here's my plan:

  • Merge the common info into this HDRI article. Make it a more general 'overview' type article, with links to the more specific and related articles.
  • Add some more example images and explainations.
  • Rename the High dynamic range rendering article to something like e.g Realtime HDRI rendering. Make it less game-specific.
  • Move some content to the tone mapping article, in particular the ghastly Photoshop CS2 tone-mapped photos.

What do people think of these ideas? --Imroy 16:35, 4 August 2006 (UTC)

Pardon my ignorance, but I thought CCDs and digital imaging happened way after Trinity, Castle Bravo and the like... gone underground, so to speak, except for Ivan (at Novaya Zemlya) and the French blasts.

Darkroom magic... masking and doing the abracadabra hand thing in collimated light, dodging and burning with more than one neg...that I can see. It's just the way the article is written, it sounds like someone went to town on Photoshop with that nuke pic. Again, pardon my ignorance si vous plais. If a digital actually exists, let me know who to talk to to get it! (talk) 08:16, 10 September 2008 (UTC)


Are there displays that are capable of showing HDR pictures - at least in a better manner than current standard consumer displays do? --Abdull 17:08, 11 August 2006 (UTC)

Yes, there are LCD monitors that turn the backlight down for dark scenes, and up for bright ones. Anyone like to find a link ? Of course that only works for DVD playback, I guess, though it could be adopted for games. Of course the pupil of your eye might contract & dilate to compensate - but are we aware of that, even on a subconscious level ?

Maybe an LCD could be furnished with a coarse matrix of backlights, one per 'tile' for displaying JPEG images ? Ah - yes, why has the 'Brightside' link been removed ? The fact that people ask the question suggests it would be worth suppling the answer, no ?

Giving examples of photos with compressed dynamic range (low-gamma) may be misleading - is that really HDR? Perhaps one could create an exaggerated example using 24 bits/pixel during image processing, vs 16 or 8 ? It is noteworthy that 'high' keeps getting 'higher' as technology advances !

I would vote for either including the old analogue silver-film based techniques in 'History', or removing the compressed images. As well as stacking layers of differently-exposed films, large-format photographers used to use very dilute chemicals and no 'agitation' to limit the maximum black levels by 'exhaustion' - see the book "The Negative" by Ansel Adams ... Not to mention 'burning-in' skies or 'holding-back' dark areas with 'dodgers' when enlarging negatives ... I suppose that 'graduated filters' are still used with digital cameras, too ? 20:56, 4 June 2007 (UTC)

Dynamic Range vs. Radiance/Tone

I would suggest that this article confuses "dynamic range" with the concept of "radiance vs. tone". Dynamic range refers to the precision and range used to store values, regardless of whether the values represent radiance information or tone information. In contrast, radiance measures amount of light and can go from zero to infinity while tone measures amount of pigment or light emited from a screen, and goes from zero to a finite maximum (say one, for simplicity). Radiance can come from rendering light in computer graphics, directly reading a digital camera's imager, or cleverly combining several photographs taken at different exposures. Tone is what you see in a photographic print or on a screen.

Tone mapping is just the process of converting radiance information to tone information, regardless of dynamic range or precision. Even low dynamic range radiance information must be logarithmically tone mapped to simulate film's respone to light and to give a natural looking photograph (if that is the desired result). Thus, to say "a high dynamic range image is usually tone mapped" is confusing, because all radiance information is usually tone mapped.

Perhaps this article should focus only on the fact that HDRI permits the storing of precise information, be it radiance or tone, across a large range from very dark to very light without loss of information. References to tone mapping could be restated as "HDRI permits precise radiance values to captured/calculated and used in innovative tone mapping algorithms that reveal detail in highlights and shadows, detail that is often lost in simpler tone mapping algorithms. HDRI also permits storing and manipulating precise tone values, which is important in digital image manipulation to prevent gradual degradation of the image as operations are performed."

—Preceding unsigned comment added by Auiow (talkcontribs) 22:11, 11 September 2006 (UTC)

New page 'Dynamic range compression' ?

Hi I think we could resolve the tensions apparent here by creating a new page 'Dynamic range compression' that covers all means of reducing dynamic range - both digital and analog/silver/film. ( Maybe Compander and Dolby Noise Reduction etc for Audio, too !)

Then this page could just be used for displays and file formats that retain the full range. Would a file with gamma < 1 as metadata in count ? ... even if highlights and shadows were clipped ? EXIF is poor at recording precise metadata: EXIF:Contrast is crude, qualitative and subjective - Soft¦Normal¦Hard - should have been an actual quantitative gamma value ! Any idea what EXIF:GainControl means ? High Gain Down ¦ Low Gain Down ¦ None ¦ Low Gain Up ¦ High Gain Up Presumably it's like the 'Brightness' knob on your CRT monitor, as opposed to the 'Contrast' one , which was really Gamma ? Or pre-fogging or flashing film ? Actually, I doubt if any display will exactly reproduce the range in most real scenes ! Conversely, any display or file format will give exact rendition of a sufficiently low-contrast scene ... The same scene will generally have a higher range if sampled with higher spatial resolution! Plus we could ask the question "How high is 'high' ?" - that will change in the future as it has with LCDs in the recent past !

— Preceding unsigned comment added by (talk) 22:37, 4 June 2007 (UTC)

Poor example image

There is an example iamge near the top of this entry. It is a nice picture and someone even though of making it a featured wiki image. I has nothing to do with HDRI since it is a jpg. This could be edited and replaced with any image and be just as valid.

— Preceding unsigned comment added by (talk) 20:16, 24 October 2006 (UTC)

HDR images cannot be displayed on a regular screen, or print. They need to be downsampled. I will reword the captions. HighInBC (Need help? Ask me) 01:36, 3 November 2006 (UTC)

HDR is not only Photomatix!

Why there are so many links to pages showing "how great" Photomatix is? Photomatix tutorial, Photomatix vs. Photoshop, ... Where is easyHDR or FDRtools (both have freeware and comercial versions)? Photomatix is not freeware, it costs $99!

— Preceding unsigned comment added by (talk) 11:17, 8 July 2007 (UTC)

Another poor example image

Image:Wiki HDR clouds.jpg

  • It may not be properly licensed.
  • Its art and technological value seems to be low to me.

I think this image is really a bad example of HDRI. It has poor contrast. It also does not show you anything. You may see that kind of view in almost every city on earth. -- Toytoy 22:19, 8 July 2007 (UTC)

I do agree, poor interest.

Julien29 (talk) 11:53, 31 December 2008 (UTC)

Confusing examples

The "blur" examples in this article are rather confusing; it's not even clear which blurred image is more desirable. Or is this merely a mathematical exercise? Perhaps they should be removed entirely. -- Beland 22:06, 25 July 2007 (UTC)

  • I agree that I don't really see how blowing highlights qualifies as "being useful". Also, the explanation is a bit lengthy and repetitive, not so interesting imho. --Nattfodd 14:21, 26 July 2007 (UTC)
  • Well, I guess I'll just remove the section then. If anyone wants to refer back to it, just check the edit history for right about now. -- Beland 18:04, 30 July 2007 (UTC)

Units of measure

The units "db" are used without any explanation of what this unit means, or how this quantity is measured. That would be a useful section to add. -- Beland 01:22, 26 July 2007 (UTC)

Poor example image

I find the images Image:HDR_example_-_exposure.jpeg and Image:HDR_example_-_exposure-1_2_3.jpg to be quite poor examples. The middle exposure looks almost perfectly like the final tone mapped image, and one has to look very carefully, possibly in high resolution, to see that the sky is burned in the middle area. The right image seems to have no interest whatsoever since there are no clipped shadows in the middle image. I suggest replacing it with a more visual example that still retains the simplicity of the subject here. I am not aware of any such image on commons, but perhaps we can find something. If not, I can contribute one of my HDR in a similar montage.

Thoughts? --Nattfodd 08:29, 7 September 2007 (UTC)

I would have to agree with you — looking at Image:HDR_example_-_exposure-1_2_3.jpg with two different grade monitors and understanding what I was looking for, I think a better example could be presented for easy grasp by the encyclopedia's audience. The high-res click-through on this image is poor quality. This is a shame since the subject matter is reminiscent of Italian perspective and light experimentation during the Renaissance, and thus highly appropriate. --Charles Gaudette 09:52, 10 September 2007 (UTC)
Make better then (by the way, how can one delete pictures?) --gilyazov 14:23, 10 September 2007 (UTC)

Examples Vs. Description

This article seems to focus solely on what HDR actually produces in terms of an image. But as an encyclopedia page, it doesn't offer much by way of what it actually is. In the first section, it explains that it is a series of techniques used to achieve a certain goal, and then goes in depth on what those goals are, yet never explains exactly what the steps are, which is what I think the article should be about. Yea, nay? AnonHat (talk) 10:01, 7 January 2008 (UTC)

Why can't we just get along ?

There is so much conflict here that I'm not going to waste our time editing the article again. Savvy folks will always read the talk pages, too - it's much more fun.

HDR (High Dynamic Range) is a very general term that can be applied to any variable that changes between extremes. It will always raise the question "How high is high?". The answer generally changes as technology improves. Dolby Noise Reduction is an example of compressing audio from a HDR sound source to fit the signal-to-noise ratio of a low DR channel such as an audio cassette, and (maybe) expanding the dynamic range again for the listener at playback.

It is ridiculous to say that it is only applicable to one particular technology, such as esoteric digital image processing or file formats. It is good to separate the synthesis of (moving) images from 3D computer models as HDRR. That is not real imaging - it is image synthesis.

"Imaging" is not the image, it is the process of creating and manipulating the image. It might be better to think and talk of imaging an HDR scene. Whether or not the finished product actually contains a high dynamic range or not, as long as it successfully conveys the imager's intentions to the viewer, it is an image of an HDR scene or object, so it is "HDR imaging" - to my way of thinking, at least. The image is not the object.

There is much that has been deleted from this article that was very useful and relevant. Mention of HDR displays has gone - seems one was removed as duplicate - did the other get moved to HDRR? Displays are just as much a part of imaging as sensors and all that happens inbetween!

History did not begin with the first computer. It seems daft to delete all mention of 'prior art'.

Probably the earliest form of DR compression was lens flare or fogging of film, which would give extra exposure to the dark parts of a light image landing on a film, raising them to the threshold of sensitivity. Ansel Adams described deliberately 'flashing' film prior to exposing it in the camera. He also used dilute developer that would get exhausted in highly-exposed areas of the film, and/or transferred the film from the developer to a water-bath to allow development to complete in shadow areas, just using the developer absorbed in the gelatin emulsion of the film.

Graduated filters and dodging shadows or burning-in skies during enlargement also help to reduce or manage HDR. They are the analogue equivalents of tone-mapping.

The simplest form of tone-mapping is just multiplying the contrast by a chosen factor called gamma. The article implies that gamma is 'corrected' < 1 to suit the 'number of bits' in the 'human visual system' ! What ??? It has more to do with sensors, storage and display ! The human eye is pretty good at handling reality.

Using lower-contrast film, developing or photo paper allows us to compress a higher DR image in silver photography. They multiply a high contrast light input by a gamma < 1 to give a lower-contrast print output. That is still HDRI, since you are imaging a high dynamic range input.

Similarly I note that digital tone-mapped images of HDR subjects are still regarded as relevant to HDR imaging, even if they are not strictly HDR images. I suppose landscape photographs are not physically constructed from landscape, and no animals are consumed in the making of wildlife photographs either. The image is not the object. It is a little sloppy to talk of anything produced outside of the laboratory or the CPU/file/memory as an 'HDR image', but English is a sloppy language. Arguably some of the tone-mapped images (eg those created from a single non-HDR image file) are actually 'Low DR', even though they look like over-compressed images of HDR scenes.

Maybe separate pages for HDRI hardware, HDRI software (HDRI processing and HDRI file formats) would deflect those that seek to delete stuff outside their narrow fields of expertise from the HDRI page ?

-- (talk) 12:35, 6 March 2008 (UTC)

I suspect that we could go back even further - HDR in Fine Art. I bet some painters applied the effect, even unconsciously. Can't think of any offhand, though. Impressionist ? -- (talk) 21:30, 14 March 2008 (UTC)

We need a new name for compressed DR ? RDR ? CDR ?

Perhaps we could be constructive by encouraging the use of a new word for the 'HDR-look' achieved by compressing an HDR image to suit an LDR medium (ie tone mapping) ?

High Acutance was used to describe the enhancement of a light-dark boundary on silver-based photographic film, caused mainly by the diffusion and exhaustion of developing chemicals. The compressed DR is a similar effect, but usually with a 'halo' over a longer range. In the example on that page, increased acutance has probably increased the DR ! Maybe it's not such a good choice.

USM =Unsharp mask is similar, but describes the process rather than the effect.

Tone mapping is another very general process - to use it to describe only one particular effect would be very bad, since increasing contrast is also tone-mapping.

RDR = Reduced dynamic range ?

[1] only finds a use in satellite thermal imaging.

CDR = Compressed dynamic range ?

[2] finds many existing uses, including CD-r = Compact Disk Recordable (CDR image could be an ISO image)
foo.CDR = Corel Draw image file

Is anyone here a user of (HDR?) photo forums or the HDR Flicker group ? Best if the users themselves define their own terminology ... but not to call reduced-DR 'HDR' ! That's how we got into this mess in the first place.

Maybe H could be the first letter of another word than 'High' ? A thesaurus [3] only gives 'Humble Dynamic Range' The abbreviation would still be ambiguous - no.

What do people think ? -- (talk) 01:05, 7 March 2008 (UTC)

It's important that we stick to what things are called, and not make up new terms. The mapping of HDR info into a lower-DR output medium is in generally a photographic rendering operation, and is specifically called "HDR rendering" in many places (e.g. here and here). It is unfortunate that the computer graphics field has a rather different meaning for exactly the same term. That's life. Dicklyon (talk) 08:06, 7 March 2008 (UTC)

Wow, there is so much HDR misinformation here. Some monitors can display HDR images, but not all monitors. Combining three exposures into one image will not give you an HDR image, no matter what processing you use. —Preceding unsigned comment added by (talk) 14:56, 28 March 2008 (UTC)

Reverted addition, why?!?!?

My addition of an example:


was reverted with summary "enough examples already, and really too many halos in tone mapping". I have no problem if people here dislike my photo (I thought it was fine since it was already appreciated in flickr) but the edit summary seems to be really meaningless:

  1. there are lots of wikipedia pages with small galleries of examples (see Tone mapping for istance) so it's not clear why 3 examples should be considered "more than enough" in a page about photography stuffs
  2. actually in my image there are no halos at all as everybody can see even looking at the wires in front of the sky - which are places where the HDR halo concentrates - (while pages like Tone mapping are full of images with many large halos without being deleted)

so maybe there are other more meaningful reasons I am missing?--Pokipsy76 (talk) 07:12, 9 June 2008 (UTC)

I agree to the removal. In my opinion, there are already enough examples in the article. The article also links to commons:Category:HDR images where intrested readers can find hundreds of additional examples. — Richie 21:47, 3 August 2008 (UTC)
I don't agree, I think the image is perfectly showing what HDR is, and there is no halo. I don't see why we should limit to 3 pictures which are actually not necessarily very interesting. I'd go for putting it back.

Julien29 (talk) 11:52, 31 December 2008 (UTC)

HDRI Intent

The article currently states that "The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes...". Maybe it's just me, but HDRI images, including the examples in this article, look anything but "accurate". Some HDMI images may look awesome and very appealing to the eye -- but "more appealing" does not always equate to "more accurate." Describing them as a more "accurate" depiction of "real" scenes does not seem... well... accurate. Many HDRI images appear very distorted when compared to reality. -- Mecandes (talk) 21:48, 20 September 2008 (UTC)

I agree; just take out "accurately"; or "to represent and appealingly reproduce" or something like that. Dicklyon (talk) 21:51, 20 September 2008 (UTC)
I agree with your general point, but not with your conclusion. Sure, HDRI is very easy to get wrong, with awful contrast and completely artificial lighting, and most examples of this page depict this pretty well, but it doesn't mean that the point of HDRI isn't to render something more realistically. There is something else to HDRI than the flickr look. --Nattfodd (talk) 10:01, 21 September 2008 (UTC)
You confuse HDRI and tone mapping. HDRI is meant for accurately representing a large range of intensity levels, whereas tone mapping is the “compression” of the high dynamic range into the lower dynamic range supported by displays and print media. And in tone mapping there are two main categories: maintaining a realistic look and making it look artistic. Flickr’s HDR images tend towards the latter. I hope this cleared things up a bit. — Richie 14:49, 21 September 2008 (UTC)
Where do you get this narrow definition of HDRI being only the capture and representation, and not also the rendering/reproduction? Much of the field of HDRI is about reducing dynamic range to make nice renderings that can be displayed or printed, and "tone mapping" is not a very good term for the range of techniques in use there, since it's a term that's more suitable for the non-local techniques, which are mappings. Dicklyon (talk) 21:27, 21 September 2008 (UTC)
One problem with HDR has always been in viewing the images. Typical computer monitors (CRTs, LCDs), prints, and other methods of displaying images only have a limited dynamic range. Thus various methods of converting HDR images into a viewable format have been developed, generally called "tone mapping". (from the article)
This separation between HDRI (for accurate representation of a high dynamic range) and tonemapping (for displaying HDR images on low dynamic range media) is also very common in the literature, such as this book by Erik Reinhard:
Reinhard, E. (2006). High Dynamic Range Imaging – Acquisition, Display and Image-Based Lighting. Morgan Kaufmann. ISBN 0125852630.  Unknown parameter |coauthors= ignored (|author= suggested) (help)
An indenpendent description is also given at the Panotools Wiki. — Richie 18:23, 23 September 2008 (UTC)
I agree with the panotools wiki lead where it says "The term is used to refer to techniques and images that are capable of capturing and reproducing scenes with a high dynamic range." Reproducing scenes with a high dynamic range requires dynamic range reduction, as Reinhard et al. point out, and some specific methods of doing so are called tone mapping and tone reproduction, they say. But I don't see them excluding those dynamic range reduction techniques from the scope of HDRI. Dicklyon (talk) 05:07, 24 September 2008 (UTC)
I see what you mean. One could consider tone mapping to be a part in the HDRI pipeline. However, from my understanding, tone mapping and tone reproduction describe the same thing, and all techniques that map high to low dynamic range are summarised by this term. — Richie 16:53, 27 September 2008 (UTC)
Yes, DR reduction is a key part of the HDRI pipeline. Until 10 years ago, the term tone mapping was used more literally, as in a map (mathematics) applied at each point. In recent years, the same term has been extended to apply to non-local operations. I don't think it's a great term for that, but it's what's used in this field. Let's not treat it as not part of HDRI, though. Dicklyon (talk) 22:06, 27 September 2008 (UTC)
That makes sense. I guess tone reproduction would be a better term then. — Richie 19:28, 1 October 2008 (UTC)

So is HDR a "good thing"?

Sorry, not really an encyclopedic question here, but is HDR supposed to be superior in some way to other digital images? I look at the second image on this page, the one of Trenčín, Slovakia, and I think it looks ghastly, as if you were walking through Candyland come to life. The one above it, of NYC, is beautiful, but then it also looks very CGI. zafiroblue05 | Talk 05:16, 18 October 2008 (UTC)

It's supposed to be an improved way to render scenes that have too much DR otherwise. It's not a new technique; it was pioneered by Ansel Adams. But being easy and automatic now, it tends to be way over-done; I agree the results are often ghastly, but sometimes that's a look that someone is after. Dicklyon (talk) 14:45, 18 October 2008 (UTC)
It is a good thing when done well, as it sometimes is the only way to capture some scenes. The problem, as has been said before, is that it's really easy to overdo the effect (that's actually what the default settings of Photomatix give you...). When done well, however, HDR processing is almost undetectable (cf for instance Image:Duolbagorni_in_Kebnekaise_valley.jpg). I also think that most images on the article page are awful examples (or rather, very good examples of bad HDR) and I would argue for their removal from the page.--Nattfodd (talk) 22:03, 18 October 2008 (UTC)

HDR examples at the bottom...

Can someone render the three exposures at the bottom into an HDR photo to showcase the final result so that people can see what the HDR process looks like before and after? —Preceding unsigned comment added by WisdomFromIntrospect (talkcontribs) 11:44, 16 December 2008 (UTC)

Update the external links

I propose to reintroduce the link I've placed on a HDR Tutorial explaining the workflow to obtain such results. Dick Lyon has already removed it twice (which I'm not sure of the procedure, since it should stay on the page and then we discuss in my opinion), as well as another link that somebody just added. The current links are very outdated and have very poor content: Linux and HDR, this is so niche that I can't understand why we keep such links, since Linux is such a niche OS and vast majority of people are on Windows or Mac OS. The first link is a commercial link, and I think it is misleading to keep it, since it adds simply no value to the article content. Stitched HDRI is a old page about pan photography more than HDR, and the Nicolas Genette article could actually stay (but from previous discussion I see it was on the list to be delisted!)

I therefore propose to replace #2 and #4 current links with the 2 following links, which would add much more usefull information:

Tutorial on HDR workflow, taking into example a swiss landscape in Lavaux
Comprehensive tutorial on HDR from Stuckincustom

Both of this links have no commercial or spam purposes, therefore they will contribute a lot to the readers knowldege on how to do HDR, since both writters have lot of experience with the technique. I then propose to remove the link on Linux and HDR, as well as the first link which is commerial. Julien29 (talk) 11:29, 2 January 2009 (UTC)

A couple of points: each link should be considered independently; it's not a trading game; if editors want to add one or both of those and delete one or both of the others, that's fine, but it's not a swap. I haven't looked at the old ones myself; my attitude is usually that old links have been accepted by other editors, and new ones deserve close scrutiny; so don't get the impression that I have expressed any actual preferences based on the contents or anything like that; you may be correct that they are "worse."
Second: please comment relative to criteria in WP:EL. What makes these links suitable? Dicklyon (talk) 17:52, 2 January 2009 (UTC)
The 2 links I'm proposing are, according to me, compliant with the WP:EL, since they are about article (tutorials) of quality which we can't retranscript in Wikipedia article, since both of them are explaining process, both with different scope (first one about the workflow, second one with more depth on the HDR settings). They are both blogs, however both are from experienced HDRi photographer. They are not commercial, and have neutral and accurate material which would be very helpful for any reader interested about practising this technique. To note, they are much more useful than other present links. Second site is however longer than first and can take more time to load for dail-up users (much less important now than few years ago). They are reliable sources, in English, with no need to register and are not with any redirection.
Therefore I do believe this is useful for any reader that want to go more in depth in this technique and should be added, and I therefore ask for placing them as external links. Dear Dick, if you have any proven objections, then please comment, if not then please let me add them since you already reverte twice the placements of links, and they should be there at the moment while we discuss instead of removing them and discussing after if we can place them. To remove other links, we can discuss separately, but I have already explained that 2 of them are totally not relevant and should be removed, which I will do as well once we agree on that. But please, talk about the relevance of the links instead of just pointing to the WP:EL without any arguments. It would greatly help to solve this case. Julien29 (talk) 18:44, 2 January 2009 (UTC)
The consensus on the question (which has been repeatedly raised in the past) has been that there shouldn't be tutorials in the external links, this is simply not the place, wikipedia being an encyclopedia and not a howto base. On top of that, the first link is not that relevant, it deals more with how to obtain the "HDR look" through tone mapping than really extending dynamic range with multiple exposures. --Nattfodd (talk) 20:46, 2 January 2009 (UTC)
You said you have reached a consensus saying no tutorial on that page. First of all, when reading all the discussion I can see that this is not true: there was indeed a discussion about keeping one link because it was a concise tutorial on doing HDR (which is the case of the first link I've placed), and no decision to kick out all tutorials. I can't see any agreement from anybody about the fact of not placing any tutorial. This is strictly your own point of view and interpretation, which is very far from being a consensus between authors (including me then since I'm participating to this page). Secondly, you'll need to explain me why the current link are kept and not the one I've added, since the links present on the page today are about a tutorial on pan photography with a bit of hdr (which has very poor interest with the subject of HDRi) and tutorial on using a very unknown software on a Linux for doing HDR, which is a OS with such niche penetration it has no reason to be mentioned here. Not to mention that some links are purely commercial. They do not add any value, whereas the one I'm adding are much more valuable for the community on wikipedia. The first tutorial is actually not about "how to give a "HDR look" but about the workflow of doing it with a single RAW exported with different exposures to extend the dynamic range, which is exactly what is HDR about.
On top of that, I see that you keep your own picture and links, and don't want other to add anything on that page: for instance you keep a link to your own gallery on the French page, and you kicked out the link I've placed on that page as well.I find this very controversial, and don't see why you didn't remove the link to your own page as well, since you seem to apply a strict application of the link politic [4]. Looking forward to understanding how you support this proven fact. Your arguments proven not to be valid, I propose to add back these 2 tutorials links into the page. Julien29 (talk) 23:53, 2 January 2009 (UTC)
Show me a diff where he added a link to his own site, and I'll remove it. As for the WP:wikilawyering, it's not becoming of you, and you're not good at it, so please refrain from that line of argument. I'm not sure what consesnsus has been discussed, but the page history shows that Nattfodd has consistently removed howto links; as have I; nobody has objected before now, and your objection as the person wanting to add one won't carry much weight. Dicklyon (talk) 00:14, 3 January 2009 (UTC)
In no way I wanted to have "lawyering" words, and if it turned out to be interpreted like this, it was not my intention, sorry for that I take it into account. I've just answered to a comment Nattfodd made. What I'm referring to is on the French page, where he deliberately removed the link I've placed (where other blogs and tutorial are present however), and he kept his own link, plus the only picture he kept on the page is his own picture as main one, placing all the other pictures which are in my opinion better to illustrate good HDR in much smaller (I've not uploaded any into it, so I'm very neutral). You say that removing howto links is needed, but then I'm asking again (for probably the 5th time now) why do we keep the current links which are howto links? Finally, there was no consensus in the discussion to remove howto links, as said before, so for the moment I can't see where is this rule coming from, since it's not in WP:EL too. Therefore I see some contradiction in how we apply the rule on placing external links in that page, which is why we are discussing it at the moment. Julien29 (talk) 01:00, 3 January 2009 (UTC)
If you're talking about French wikipedia, you can take that up there. As to removing howto external links, I'm not sure. There's WP:NOTHOWTO, but that's not about external links. The history on this article, however, is that there used to be a whole lot of external links, and now there are not so many, because most have been found inappropriate. If you think some of the current ones are inappropriate, please do feel free to remove them, as I said before. If someone puts them back, we'll here about why. Dicklyon (talk) 04:23, 3 January 2009 (UTC)
I've removed the 4 links we currently have, since according to what I've mentioned above, none of them are compliant with the rules you've presented. Now we need to all agree on the links we can place and get the consensus about it. I've presented 2 links, which I'm writting again, and that depsite being howto are not forbidden to be mentioned as external links by the wikipedia rules (it's however forbidden to write an article as a howto).
Tutorial on HDR workflow, taking into example a swiss landscape in Lavaux
Comprehensive tutorial on HDR from Stuckincustom
On top of that, I'd also put a link to the Flickr gallerie of HDR, which is, despite quality concern, one of the main place online to find HDR and make a oneself opinion on it. Quality changed since 2006, when it was removed last time.
I let you propose any other links, which would comply to the discussion we have now.Julien29 (talk) 07:20, 3 January 2009 (UTC)

Choosing external links

Now that Julien29 has boldly removed the remaining four external links, let's consider what links will actually help the article. Here are the four just removed:

and the two that he has recommended:

and the old Flickr link that he re-recommends:

I haven't really studied them much yet, but I do agree that the Flickr link is a pretty diverse collection of HDR images, including some pretty bad ones and over-done ones, but I like it. Dicklyon (talk) 07:29, 3 January 2009 (UTC)

Of the four deleted, I would definitely keep the first one, as it is indeed very informative and in-depth information that is not easy to find elsewhere. The rest can go, I think, as they are more of the tutorials variety, and not very good at that. If we decide to have tutorials in the links (which I feel is not necessarily a good idea), then I think we should limit ourselves to only one, and the second one (stuck in customs) is definitely a better candidate.
As for flickr, the link had been repeatedly removed in the past, for reasons discussed on this page (mostly that it's misleading as to the nature of HDR imagery). I personally don't really care either way, but I still think it's a slippery slope. --Nattfodd (talk) 12:44, 3 January 2009 (UTC)
I looked at the first one, and agree that it's broad, deep, independent, academic, and generally good. So I'll put it back. As the the gallery and howto links, I think I agree that the "slippery slope" of having one invites more, and that's generally a problem. So I'll do without any of those unless we hear specific arguments for some. Dicklyon (talk) 18:17, 3 January 2009 (UTC)
I'd still go for more external links, since the first one is, in my own opinion, not relevant for the vast majority of people. I'd still go for the 2 HDR tutorials, since they are different: first one is for "single RAW exposure HDR workflow tutorial" (perfectly on spot with the article), and second one is "multi exposure RAW HDR tutorial" (also on spot with the article). For the Flickr Gallerie, I'd add it: Nattfodd mentioned that it's a "slippery slope" to place Flickr gallery, but has no objections to place a link to his own personal webiste gallery on the French page, in total contradiction with what he says. So I'm definitely convinced we should have Flick Gallery on external link on top, since it's what the vast majority of people are doing on HDR, good or bad, we are not here to judge on quality which is very subjective (I'm not judging the quality of your personal website gallery for instance). What you can see on Flickr is what people are seeing everyday, and this is probably also why they come on this page to get more information: "what is HDR and how to do it?". It's much more relevant than first link anyway. Finally, up to you to propose more sites, but I don't think such conservatism is beneficial to the reader. --Julien29 (talk) 08:59, 4 January 2009 (UTC)
Please refrain from ad-hominem arguments. Besides, the link to my gallery is on the french page: if you want to remove it (which I wouldn't actually oppose, as long as the other links are cleaned as well), then take the discussion there. As for tutorials, the goal of the wikipedia page is to answer the question "What is HDR?" and not "How do I do HDR?": for me, those tutorials should not be linked (and they can be found easily anyway through a web search). Wikipedia is not a link directory. --Nattfodd (talk) 16:21, 4 January 2009 (UTC)

Gallery and more HDRs

I'd like to put my HDR (shown on the right - the one of the White House) on here, and create a gallery for the images such as the one above which was rejected. Should I?


HiraV (talk) 21:08, 1 April 2009 (UTC)

No, please don’t start a gallery of ‘HDR’ images here – have a look at commons:Category:HDR images instead.
PS: Your photo has been reverted to the original one. — Richie 22:36, 12 April 2009 (UTC)

Example text no longer matches image

Someone seems to have changed the "Exposure examples" image without changing the text. I don't know enough about the subject to know whether parts of the text are still correct (the EV values, for instance). But the current example definitely doesn't have "bright clouds in the sky". -- Creidieki 11:00, 5 June 2009 (UTC)

They are reflected in the sphere, see the left most dark image's clouds and the final image. ---RJFerret: talk, 04:26, 14 July 2009 (UTC)

Bad examples of HDR

This article shows bad examples of HDR. HDR has not been created in order to have this cheap "dark storm" effect on the photos, it has been created in order to have more realistic photos. Why promoting the cheap use of HDR?-- (talk) 12:40, 27 July 2009 (UTC)

Distinguishing HDRI and exagerated contrast photography

It seems to have recently become fashionable to create art-photographs with extremely exaggerated contrast using HDR tone-mapping tools. (i.e. the 'bad' examples in the section above) In these cases the HDR part of the process is often nearly incidental and really only relevant in that it prevents the enormous contrast boosting from making noise visible. The resulting sRGB images are often called "HDR" after tools used to create them.

So we now have three things commonly called "HDR": Images with a true linear dynamic range far beyond sRGB, Renditions of the former for conventional display devices created via tonemapping to achieve the most perceptually correct result, and art works which use tonemapping to create striking images without a particular regard to accuracy, which may or may not have started with an image with unusually wide dynamic range.

I think that its important the that article deal with these distinct but overlapping uses rather than mixing them together. Is anyone aware of a authority we can reference in order to find distinct names for these different uses? --Gmaxwell (talk) 00:37, 18 August 2009 (UTC)

Tone mapped output is LDR, not HDR

"...using local neighbourhood processing (tone-remapping, etc.), into an HDR image." But I feel a need to read the patent before correcting that. --Darxus (talk) —Preceding undated comment added 19:29, 18 August 2009 (UTC).

Massive rewrite by Darxus

I haven't read it all, but I disagree with many of the details that I've looked at. To start with, the lead is no longer even in proper form; the old lead was better; second, whole sections were removed with essentially zero explanation. Darxus, please slow down, tell us what you're up to, and allow others to give some feedback and interact with your edits. Dicklyon (talk) 15:44, 20 August 2009 (UTC)

All of my edits have been commented (with a couple extremely minor exceptions). The lead has been largely reverted by Richie. I was not aware of my violation of proper form, I apologize. I won't modify the lead again before reading WP:LEAD. (And thank you for the term "lead", with which I was not familiar). I did nothing "with essentially zero explanation", particularly removing whole sections. The one section I remember removing was on synthetic HDR, with a comment that High dynamic range rendering#History more than covers its previous contents, with a wikilink in the lead, and a spot at the top of the See Also section. Second from the top. Just moved to the top. I love feedback. --Darxus (talk) 01:36, 21 August 2009 (UTC)
Darxus, it's just too much to absorb at once. Mostly your edits look good. But try to listen when I point out errors like the log thing, since as you noted your math is not so good, and neither is your psychophysics. You left a section empty except for a main link; it is conventional to put at least a brief summary paragraph in the section. Thanks for working on the Debevec images; I had warned the guy who uploaded those, but then forgot to follow up and do something about them. Dicklyon (talk) 06:34, 21 August 2009 (UTC)
When most people read "HDR", they think of the results of excessive tone mapping. I would like to get a very concise sentence addressing that into the end of the Lead. --Darxus (talk) 21:12, 21 August 2009 (UTC)
I'd also like to get a note in somewhere that tone mapping often causes people to think they're looking at an impressively dramatic work of photography, when they are only looking at a work of mildly interesting filtering. --Darxus (talk) 23:28, 21 August 2009 (UTC)
Addressing what most people think is only possible via a source. What have you got? Dicklyon (talk) 23:43, 21 August 2009 (UTC)

"omit the flaky untruth" - user:Dicklyon, referring to "The human eye responds to changes in light intensity on a logarithmic scale."

"..the eye also responds logarithmically to brightness." -, as previously wikilinked.

"This derivative is nearly a constant proving that intensity response of cones and rods can be modeled as a logarithmic response. " -

"Eye response to signal intensity (brightness) is logarithmic for the most part (Weber's law)." -

In addition to the original:

"The human eye responds to changes in light intensity on a logarithmic scale." -

--Darxus (talk) 01:18, 21 August 2009 (UTC)

As I said before (I forget which talk page), it's an often repeated (esp. on random web pages including in wikipedia) but incorrect statement. The "for the most part" is one way to fix it up a bit; but it's been known for a long time that something like the Stevens' power law is always a better approximation than the Weber–Fechner law. If you put sufficient qualifiers, like at least the word "approximately", it might be OK, but if you want to really be right, you could say something more accurate. For example, Stevens wrote a book that covers the history of his power law relative to the Weber–Fechner interpretation over the years. Dicklyon (talk) 05:18, 21 August 2009 (UTC)
That conversation thread is here: Talk:Logarithm#Why_logarithms?
In summary, both Weber–Fechner_law and Stevens'_power_law say vision is logarithmic. --Darxus (talk) 05:29, 21 August 2009 (UTC)
Well, no, a power law is not logarithmic, though it's close over a moderate range. Dicklyon (talk) 06:05, 21 August 2009 (UTC)
Ah, you're right, "a" is a constant for any given stimulus.
But Stevens'_power_law#Criticisms still seems pretty thorough: "Many researchers in psychology and psychophysics would now reject Stevens' power law completely, suggesting that the results were due to inherent biases." --Darxus (talk) 06:36, 21 August 2009 (UTC)
Smitty went overboard in claiming his power law to be some kind of truth, and got criticized for that; this article reads like it got input from someone who didn't like him much. But I don't think any of the criticism ever suggested that it wasn't an improvement on the Weber–Fechner law. Dicklyon (talk) 06:47, 21 August 2009 (UTC)

Violation of Paul Debevec's copyright.

The images in High_dynamic_range_imaging#Tone_mapping are derivitives of Debevec's work, downloadable here:
The image info says they were uploaded by the owner, who was not Debevec (confirmed). I haven't nominated for deletion yet because I wanted to see if Debevec could be convinced to license them and use the existing file info etc. as references for uploading correctly attributed replacements first.
Emailed Debevec: Tue, 18 Aug 2009 01:46:45 -0400
Recieved response: Tue, 18 Aug 2009 00:57:07 -0700

I would be happy to have my HDR image of Memorial Church used by Wikipedia

with appropriate attribution (which appears not to be the case.) How would

we make that happen? Do you work for Wikipedia?
— Debevec

Sent second email: Tue, 18 Aug 2009 14:41:07 -0400
--Darxus (talk) 04:38, 21 August 2009 (UTC)

Yann deleted the images due to copyright violation. I still haven't heard back from the creator. I just notified him of the deletion and asked again if he's willing to release them under an open license. —Darxus (talk) 15:05, 27 August 2009 (UTC)

LCD display dynamic range

The value I provided is for one of my monitors, from the manufacturer's website. I don't really want to cite it because that seems a little too spammy. --Darxus (talk) 05:51, 21 August 2009 (UTC)

Demonstration section

It's not clear to me at all what the relevance is between this and the rest of the article. There needs to be a better explanation or it should be removed altogether. -- (talk) 23:01, 21 August 2009 (UTC)

I agree, it's not at all clear what those awful looking images are purporting to illustrate. Dicklyon (talk) 00:03, 22 August 2009 (UTC)
Do you see differences between the original and the other two? --Darxus (talk) 02:26, 22 August 2009 (UTC)
It shows the relationship between an HDR image and an LDR image, with the first representing HDR, and the second and third representing LDR. --Darxus (talk) 02:32, 22 August 2009 (UTC)
So it's just showing how much worse you can make a decent image look by reducing its contrast? Let's lose it. Dicklyon (talk) 07:06, 22 August 2009 (UTC)
It's showing the difference between HDR and LDR, within the dynamic range which can be displayed on a computer monitor, which I believe is very useful. --Darxus (talk) 11:40, 22 August 2009 (UTC)
I don't think it shows that, but if anyone else thinks it's useful, they should say so here and we can consider it. Dicklyon (talk) 21:58, 22 August 2009 (UTC)
How do you not think it shows that? Do you think the math I provided was a lie?
"This simulates conversion from 15 EV (±2 EV with an 11 EV sensor) to 9.5 EV (LCD monitor) by converting from 9.5 EV (LCD) to 6.0EV."
9.5 EV is 63% of 11 EV.
It shows a full range jpeg next to two versions with level ranges reduced to 63%. "Levels... range to 47 to 209", which is a range of 162, which is 63% of the full (0-255) range. --Darxus (talk) 00:00, 23 August 2009 (UTC)
There is clearly room for improving the description and original image (something more contrasty would be nice). --Darxus (talk) 00:01, 23 August 2009 (UTC)
I looked at your "improved" version, but I still don't see the point of this "demonstration"; I think that the "63%" quantification based on numbers of levels in a gamma-compressed file is flaky; the whole concept is original research at best. Dicklyon (talk) 02:33, 23 August 2009 (UTC)
So you just want a reference stating that the number of levels in a gamma-compressed file correspond to EV range? --Darxus (talk) 02:45, 23 August 2009 (UTC)
Well, that's not going to be found. But some kind of source that suggests a demonstration of this form might work. What is it that you think the 63% represents? Certainly it's not 63% of the EV difference, nor of the contrast ratio, nor anything else I can think of besides numbers of levels in a gamma-compressed representation, which is not a dynamic range. Dicklyon (talk) 03:18, 23 August 2009 (UTC)
So you're saying Levels in GIMP is not a logarithmic scale? --Darxus (talk) 03:24, 23 August 2009 (UTC)
Right. See gamma correction and sRGB. It's approximately power law. Dicklyon (talk) 03:29, 23 August 2009 (UTC)
Notes for further reading: GIMP manual Levels, RGB-values -> f-stops?, "binary data in still image files (as JPEG) are explicitly encoded" - Gamma correction (cool). --Darxus (talk) 04:04, 23 August 2009 (UTC)
Apparently erwinv on dpreview is as confused as you are about what logarithmic means and about how images are encoded. Dicklyon (talk) 04:06, 23 August 2009 (UTC)

"For the sRGB colorspace, the relative luminance of a color is defined as
where R, G and B are defined as:" --Darxus (talk) 16:48, 23 August 2009 (UTC)
That page goes on to say that the relative luminance corresponding to the sRGB levels 0 to 255 are, in perl:
$normallevel = $level / 255;
if ($normallevel <= 0.03928) {
$luminance = $normallevel / 12.92;
} else {
$luminance = ( ( $normallevel + 0.055 ) / 1.055 ) ** 2.4
This outputs a range of 0 to 1. The middle 63% the range corresponds to level / luminance:
119 0.184474994500441
233 0.814846572216101
So would you folks be okay with me regenerating that Demonstration section using the range of levels 119 to 233?
Oh, I forgot to link the reference for the previous formula: - it references [the sRGB spec] and I'd dig a reference out of there.
--Darxus (talk) 17:28, 23 August 2009 (UTC)
New images using luminance values of sRGB color space:
Full monitor range 63% of monitor range
Clouds Dusheti.jpg Clouds Dusheti drclipped.jpg
Ourapteryx sp1.jpg Ourapteryx sp1 drclipped.jpg
--Darxus (talk) 17:40, 23 August 2009 (UTC)
Luminosity of sRGB Levels --Darxus (talk) 17:58, 23 August 2009 (UTC)
Even without the math I think it is useful to show what a reduction of dynamic range looks like, within the range of computer monitors. --Darxus (talk) 19:56, 23 August 2009 (UTC)
That's just crazy – 63% of the linear luminance range gives you a contrast ratio of less than 3:1, which is ridiculously low. Clipping the dark end at flat gray that way looks nutty. You could take the lower 63% of the sRGB range and still have a contrast ratio of about 2000:1. If you want to construct a demonstration of what reduced dynamic range looks like, at least find a source that does so. Dicklyon (talk) 20:04, 23 August 2009 (UTC)
I think my math was wrong because I was comparing 63% of the log of the relative luminance to 63% of the (linear) relative luminance. Converting the 0 to 1 range of relative luminances is giving me a bit of trouble. Can I just multiply the linear luminances all by a large enough number to make all the logs positive?
The fact that the output contrast is "ridiculously low" does not make it incorrect. Clipping the dark end to flat grey is precisely what reducing dynamic range does here. (It clips the light end to a flat grey as well.)
The possibility that nobody has demonstrated dynamic range reduction within the range of a monitor isn't a reason not to figure out how to do it. --Darxus (talk) 20:17, 23 August 2009 (UTC)
Yes, a big scale factor can be used to make all the logs positive; however, that shouldn't matter, since it won't affect the differences of the logs, which is the dynamic range that you probably intend to reduce to 63%. Dynamic range is usually limited by noise at the dark end, not by clipping. As for "The possibility that nobody has demonstrated dynamic range reduction within the range of a monitor isn't a reason not to figure out how to do it," I agree completely; knock yourself out; but wikipedia is not the place to report it, per WP:NOR. Dicklyon (talk) 20:23, 23 August 2009 (UTC)
What about clipping the range of levels to an arbitrary range and saying "this is what dynamic range reduction of an arbitrary amount looks like within the dynamic range of your monitor"? We currently have no graphical representation of what any difference in dynamic range looks like, and this would provide that. --Darxus (talk) 20:38, 23 August 2009 (UTC)
Not without a source. So far all of your original attempts to demonstrate what reduced dynamic range looks like are flawed. That's one reason we don't put original research into wikipedia; who gets to decide when it's reliable enough? It's better to publish it first some place with editorial oversight, after which we can refer to it here. This is not the place to get creative. Dicklyon (talk) 20:41, 23 August 2009 (UTC)
So you feel that we have not established that reducing the range of sRGB levels = reducing the dynamic range of an image? --Darxus (talk) 20:47, 23 August 2009 (UTC)
I don't understand why you're asking me that funny question and trying to put words in my mouth. Dicklyon (talk) 20:55, 23 August 2009 (UTC)
I asked about showing an LDR image next to a version with an arbitrarily clipped range of sRGB levels, as a representation of what an arbitrary difference in dynamic range looks like, and you said "Not without a source." I don't see any way to interpret that, other than your belief that we have not established that reduction in range of sRGB levels = reduction in dynamic range. Why can't this be done without original research? --Darxus (talk) 21:05, 23 August 2009 (UTC)
Please just re-read the lead at WP:NOR. Without a source, what have you got? Dicklyon (talk) 21:24, 23 August 2009 (UTC)
I re-read. The GIMP documentation states that its Levels are (unless overridden) sRGB levels. The sRGB spec states that its levels are a scale of luminance. Are you suggesting that it is original research to interpret these two sources as meaning that a reduction in Levels in GIMP is a reduction in dynamic range? I am, currently, just suggesting showing two images - an original, and one with a reduced range of Levels, and stating that the former has a greater dynamic range than the latter. Because we have no representation of what a difference in dynamic range looks like. --Darxus (talk) 21:58, 23 August 2009 (UTC)
That's not what I'm suggesting. Just that your demonstrating of low versus lower dynamic range is "original research" of a sort. If you don't find anything like it in a book, it's a good sign that it's not really needed. Dicklyon (talk) 23:01, 23 August 2009 (UTC)

Category:HDR imagesCategory:Tone mapped images

Nominated for renaming.—Darxus (talk) 20:48, 24 August 2009 (UTC)

Article rewrite

Dear Darxus,

as much as I appreciate your work on this article, I think that the article has not improved since you started editing about two weeks ago. And this is why I think so:

  1. The article currently starts with an acceptable lead, but is immediately followed by an Example section that shows some images with seemingly random EV values without explanation. Additionally, there are two tone-mapped HDR images with their captions essentially reading ‘good’ and ‘bad’. Judging by your other edits, your main motivation appears to be to make clear that the ‘Flickr-style’ is not all there is to HDR and tone-mapping. While I agree with this, I don’t think you make a convincing case in the article.
  2. The Photography section is frankly incomprehensible and littered with random EV numbers which will not mean much to the average reader. Also, this article should not only be about HDR in photography, as there are also other uses that might be outside of your area of expertise, such as HDR in visual effects. Additionally, I would prefer the term ‘f-stops’ to ‘EV’ in the context of HDR.
  3. The History section exploded to twice the length and now sports eight sub-section irregularly spread over time (why is there 1993 stuff in the 1980 section? and why is there 1996 and 1997?). I feel that this is excessive, and that it should be shortened to a few paragraphs, maybe with a division between history in (film-based) photography and the recent revival (1990s and later).

I am sorry for these harsh words, but I hope you will strive for a more readable article in the future. Thanks. — Richie 23:32, 28 August 2009 (UTC)

Richie, thanks for your help here; Darxus is obviously a smart and well-intentioned guy, but I agree some things are off. Like the EV numbers, which I can't quite imagine what they have to do with; normally, a higher exposure value represents less exposure, so that pretty much rules out my first theory, which was that they were calculated from shutter speeds and apertures. If they were exposure compensation settings, it's hard to imagine how they came to have those funny decimal values. For the purpose of the article, I've relabeled them with what seem sort of likely as approsimate values in stops, although they don't really make sense. Hopefully Darxus can go from there to better numbers. Also, Darxus is pushing his POV that tone mapping and HDR should refer to the more narrow concepts that he wants them to refer to. That needs a bit of discussion first, I think. Dicklyon (talk) 06:53, 29 August 2009 (UTC)
That's nice to hear, thanks. They are exposure compensation settings, as calculated by qtpfsgui, the program that did the merge to HDR, from the exif tags (of shutter speeds and apertures). I agree with discussing things more. —Darxus (talk) 09:58, 29 August 2009 (UTC)
Maybe it helps to know that these shots were selected from a set bracketed in 1/3 EV increments? —Darxus (talk) 10:03, 29 August 2009 (UTC)
Doesn't help much. Can you check what it's doing? Exposure value computed from shutter speed and aperture would go the other direction; and it's not clear where it's getting values that aren't 1/3 stop increments. Can you list the shutter and aperture settings for us? Dicklyon (talk) 22:22, 29 August 2009 (UTC)
The shutter speed and aperture settings are in the exif tags of the originals:
Aperture  : 2.7
Shutter Speed  : 1/30
EV  : 8
Aperture  : 2.7
Shutter Speed  : 1/4
EV  : 5
Aperture  : 2.7
Shutter Speed  : 2.5
EV  : 1.7
Aperture  : 2.7
Shutter Speed  : 15
EV  : -1
Darxus (talk) 02:01, 30 August 2009 (UTC)
I added approx. EV values, called f/2.7 f/2.8 and using the table at exposure value. Probably what was in your Exif were differences relative to the camera's meter's opinion of a good exposure; such differences usually run the other direction than the actual exposure values. The differences are all close enough to 3-stop intervals that we should probably call it that. Or just put the actual exposure times. Dicklyon (talk) 02:23, 30 August 2009 (UTC)
The only reason this article is biased towards photography is that HDRR was already broken off. The history section needs work. The sub-headings went in as part of my first attempts at sorting the history content that was previously in the article. I don't think removing them (without further modification) would be an improvement. The only increase in size was the addition of 2005 and 2006. The 2006 quote is large, but I think useful. But I would have no objection to it being reduced (I originally only included the first paragraph). I don't mind the harsh words, I appreciate the feedback, thanks. —Darxus (talk) 09:58, 29 August 2009 (UTC)
Between the 1997 and 2005 items, there was a bit of a splash in 2003, in case you want to add something about that. I took out the 2006 item, but it could go back if there's an independent source saying something good about it. Dicklyon (talk) 22:31, 29 August 2009 (UTC)
Qtpfsgui is historically significant because it was the first free software to allow merging to HDR. It is easy to find web sites that say it is the best free HDR software, if you think that would be useful. —Darxus (talk) 02:06, 30 August 2009 (UTC)
Yes, a source is needed to establish why you're mentioning it. Dicklyon (talk) 02:15, 30 August 2009 (UTC)
I mis-typed - first free GUI HDR software. It was and is built on top of pfstools, which does the same from the command line. But the GUI is far more popular. ―Darxus (talk) 02:08, 30 August 2009 (UTC)

Where is it wrong?

CaptureNX 1.3 histogram denotes, vertical ordinate represents number of pixels at each luminosity level while horizontal axis represents luminosity level. i can accept what is current definition as luminance range of a scene being photographed, at specific ISO speed as may i add as imposure. The use of ND grad to increase dynamic range is brilliant! That's High Dynamic Range by my standard.

Although i would not bet on my definition against a researcher, i do not see what is so high about 16,384 color space tone mapped onto low 256 color space. Or a color space rendered onto another one. If HDR is really that high, it would not require exposure bracketing - would it? Just another kind of Helicon with her focus stacking - maybe? ESCapade (talk) 00:10, 30 August 2009 (UTC)

Spatial Image Based Lighting

Has anyone played around with adding 3D data to HDRs to move the lighting info in from the hoizon? There are two places where I have seen people talking about it; Jeremy Pronk (Animal Logic Lighting TD for 300) at and REALVIZ . At Siggraph this year (07) I saw the process which ILM used to add in the 3d Data to HDRI that they used in Transformers. What I saw on ILMs show reel went past what was mentioned in the CGW article described (July 07 I think.. transformed) Looks like they were adding primatives to the HDRs that they got from the 8K mirror balls - Similar to what I saw on the REALVIZ Site.

Does anyone have any feedback on the methods? I am not a 3d user (I ordered Maya 8.5) or a lighting specialist, but I really want to get a good concept of the State of the Art. The reflections on the metallic bodies in Transformers were awesome. —The preceding unsigned comment was added by Mblanton78 (talkcontribs) 21:36, August 21, 2007 (UTC).

HDR sensor

From the article: "This composite technique is different from, and generally of lower quality than, the production of an image from a single exposure of a sensor that has a native high dynamic range" Hello? A sensor that has native high dynamic range? Someone want to show an example of said sensor... I'm raising the BS flag. —The preceding unsigned comment was added by Upshot (talkcontribs) 16:37, August 22, 2007 (UTC).


"HDRHTML is a technique for embedding an interactive multi-exposure viewer of HDR images in web pages." Neat. What are the chances of getting this (javascript) supported on wikipedia / wikimedia? —Darxus (talk) 10:00, 30 August 2009 (UTC)