Talk:Wratten number
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1B
[edit]Is that 1B skylight exist in Kodak-Wratten products? Or just by other manufacturers? 203.185.57.117 14:26, 23 July 2007 (UTC)
Decamired number
[edit]Another important example of a wratten-like-but-not-wratten-number is a decamired number (1/10th of a mired) which is a measure of color temperature (1 decamired = 100000/temp°K). Eg a "B13" filter shifts color cast by 130 mireds towards the blue or higher kelvin values (cooling), and an "A13" shifts it the other way (warming). Like dioptres and focal length, adding and subtracting mired values is much easier than calculations in °K.
This Rodenstock brochure gives the following decamired equivalents of (Kodak) wratten filters (and their exposure values):
| wratten | decamired | EV |
| 81A | A2.5 | -0.3 |
| 81EF | A5 | -0.6 |
| 85 | A11 | -1 |
| 85B | A13 | -1 |
| 82A | B2 | -0.3 |
| 82B | B3 | -0.6 |
| 82C | B4.5 | -1 |
| 80B | B11 | -1.6 |
| 80C | B13 | -2 |
Redbobblehat (talk) 13:01, 26 August 2008 (UTC)
- This is a good point and I have added a mired discussion to the article. However, the mired shift claimed for each Wratten filter varies by manufacturer; I have gone with a reference from 1975 to provide a list of mired shift values for the Wratten numbers,[1]: 37 supplemented by catalogs from Rodenstock,[2]: 7 B+W,[3]: 18–21 and Hoya.[4]: 58–59
- Cheers, Mliu92 (talk) 17:19, 8 August 2024 (UTC)
References
- ^ Smith, Robb (1975). "3: Filters for Color Photography". The Tiffen practical filter manual. Amphoto. pp. 33–44. ISBN 0-8174-0180-6. LCCN 75-21574. Retrieved 8 August 2024.
- ^ "Rodenstock Quality Filters and Aspherical Magnifiers" (PDF). LINOS Photonics GmbH & Co. KG. 2020. Retrieved 8 August 2024.
- ^ "B+W Filter Handbook" (PDF). Jos. Schneider Optische Werke GmbH. Retrieved 7 August 2024.
- ^ "Hoya Filter Catalog" (PDF). Hoya Filter. 2016. Retrieved 8 August 2024.
Mliu92 (talk) 17:19, 8 August 2024 (UTC)
Photos
[edit]What about a before-after comparison photo for each filter? I think that'd help this article *A LOT*! --85.178.99.78 (talk) 14:03, 10 August 2011 (UTC)
As a professional who uses Wratten filters in scientific photography, I can verify that this article does not contain original research. It is a utilitarian article providing useful information for photographers, and as such is well within the charter of an encyclopedia. Kodak issued consumer publications with similar information up to at least 1965, but nothing recently.Gary Settles 18:03, 31 July 2015 (UTC) — Preceding unsigned comment added by Settles1 (talk • contribs)
Filters for infrared photography
[edit]I was comparing filters and I see that Hoya states that their R72 filter "does not let any wavelengths before 740nm pass through". According to the table, that matches the Wratten 87, not the 89B. Which is correct? Or do different makers make different R72 filters? 2600:8800:1220:5D00:8DC7:394D:283D:59F9 (talk) 17:18, 8 November 2023 (UTC)