|WikiProject Color||(Rated Start-class, Mid-importance)|
I'm curious as to what hardware, specifically, utilizes the extra byte in 32-bit truecolor for the implementation of transparency. I've always been under the impression that 32-bit depth in the context of graphic display is exactly the same as 24-bit depth, with the extra byte purely for padding. An actual pixel (on the monitor) cannot be partially transparent, so if the extra byte is used for this purpose, it would have to be a capability of the video card.
Now, this is distinct from 32-bit image files (such as PNG), which clearly (no pun intended) may have an 8-bit alpha channel; this, of course, can be used to layer images and achieve transparency; however, the current article implies that GUI effects involving transparency somehow take advantage of the extra byte. Is this true? Do newer video cards utilize the extra 8 bits? -- Wapcaplet 19:06, 19 Oct 2004 (UTC)
Well, when an operating system draws something such as a menu, it usually has an off-screen bitmap for it. If the *offscreen* bitmap is 32bit, you can use the extra byte for the transparency of the menu as you copy it to the screen. As far as i'm aware, if the screen is also 32bit, the graphics card can accelerate translucent blitting of the bitmap for you, otherwise the CPU has to do it. On the actual screen bitmap, the extra bytes are ignored. -- Lumpbucket
whilst that image in its origial form may have contained every color in the 24 bit RGB space, it was totally mangled to the point of being basically meaningless by the scaling process, also the image description page has no infomation on how the colors are laid out. Therefore imo placed directly it mislead more than it added any usefull information and even as a media: link to the proper image its value would be minor at best. Plugwash 02:01, 3 November 2005 (UTC)
- Description added in the image description page. Maybe you will reconsider your position. Marc Mongenet 22:50, 13 November 2005 (UTC)
Thanks for adding the info but my original comment still stands. That image only shows anything at all when displayed at actual size. scaling it down just destroys it effectively turning it into a red/green fade with a fixed or meaninglessly patterened (depending on the exact scale factor) blue component. Its simply not feasible to show off every color in the 8*8*8 space in a reasonable sized image and even when you do look at the full sized image many of the colors are indistinguishable to the human eye anyway.
I get the feeling that sometimes wikipedia suffers from a desire to get at least one image into every article even where that image isn't really very informative or is even misleading. Plugwash 00:46, 14 November 2005 (UTC)
- You're right, it's a bad illustration. It's more of a curiosity. Marc Mongenet 23:01, 14 November 2005 (UTC)
I believe that this particular term (as a runtogetherword)originates with the X Window System. X servers may implement multiple color models, called "visuals", which are given a type. This article describes the models known to X as TrueColor and DirectColor. (The difference between the two is that DirectColor visuals send each color component through an application-defined mapping before displaying. This is analogous to StaticColor versus PseudoColor, where the color map in the former is fixed and in the latter can be changed.) In any event, that would put the origin some time between 1984 and 1987 if correct. Does anyone have a citation antedating 1987? 121a0012 04:21, 16 February 2006 (UTC)
Useful demonstration images
For anyone who wishes to enhance the article visually, there's a series of image I've uploaded to the Commons:
- Image:Park-TruColor-24BPP.png (24-bit truecolour reference image)
- Image:Park-HiColor-16BPP.png (16-bit highcolour version)
- Image:Park-HiColor-15BPP.png (15-bit highcolour version)
The thing is, I don't know how to incorporate it into the articles, because 1) I don't know how to fit the images, even as thumbnails, without wreaking havoc on the page layout, and 2) when presented as thumbnails, the scaling resamples the images, thereby rendering them useless for the colour depth demonstration unless the reader follows the links to the full-sized images. --Shlomi Tal ☜ 20:32, 24 June 2006 (UTC)
Hey, I realize that this is not exactly the forum for this question, but I am looking for a relatively obscure answer that no one has been able to help me with so far. I'm trying to make stimulus for a psych experiment using CIE space, so I made it in photoshop with LAB color, a CIE space, but I can't save it as anything but a Tiff which most other applications won't load. I can save it as an 8-bit LAB color tiff, which will sort-of load, or a 16-bit RGB color .PNG file, which will load. The problem is that the two look very different, and I dont know which is closer to the true 16-bit LAB color. Any ideas? thanks and sorry for posting a somewhat irrelevant question here.
color depth of the eye
"The human eye is popularly believed to be capable of discriminating between as many as 10 million colors."
Uhm, what is this rubbish?? It is unsourced and uses weasel words. And, furthermore, my eye, which is hardly very sensitive, can definitely see more colors than 24-bit color allows. 18.104.22.168 23:15, 28 January 2007 (UTC)
- I've added the reference that's in the Color article to this one. 22.214.171.124 20:11, 8 November 2007 (UTC)
Truecolor is the color
Where did this information come from? I think that what the text is describing is a chunky graphics mode. There is probably a correlation between the widespread introduction of chunky graphics modes and the development of video hardware that can handle millions of colours rather than thousands, but I don't think the word 'truecolor' is usually applied to chunky modes. - Richard Cavell (talk) 10:50, 13 December 2008 (UTC)
- Former Amigaian? Anyway, chunky and planar graphics refers to how the bits making up a pixel is stored; not how the colors are represented. IOW, chunky graphics can use both indexed and direct color modes. As for True Color, www.poynton.com says:
- True colour is the provision of three separate components for additive red, green and blue reproduction. True colour systems often provide eight bits for each of the three components, so true colour is sometimes referred to as 24-bit colour.
- Not quite what either section describes, go figure.--Anss123 (talk) 15:08, 13 December 2008 (UTC)