"bradadad" wrote in message
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What are the rgb numbers for studio gray seamless paper? I think it will give me a baseline to work with while color correcting some photos I did shot against "studio gray" paper.

There is only one simple case for which an answer exists to your question. In complete darkness, the value is RGB(0,0,0). Increase the light one iota, and several factors kick in to make a simple answer to your quesiton well nigh impossible.

For starters, the rgb values depend on your PhotoShop working profile - sRGB, Adobe RGB, ColorMatch, Apple RGB, or other?

Then, the rgb values of the paper, and any object, depend on the intensity and color temperature of the light you are lighting the paper with.

Finally, even if you specify D65 lighting, and Adobe RGB, the rgb values of your studion grapy paper will change due to reflected light from nearby objects.

For all these reasons, it is very rare that a uniformly colored object actually has the same hue throughout, nor should it. A wall that appears the same brightness and hue does not look like a wall at all, but instead an empty space with no dimension or distance. The fact that objects vary in their brightness and hue has been used for centuries to make better paintings. This knowledge is also used to make our photographs better, and that is where the encouraging news lies - all of these things may be used to advantage to add interesting and realistic color variation to our images.

So start by doing the best you can to provide uniform lighting, calibrated equipment, etc. Then realize that, even in a studio setting, there are things that you cannot control. In the end, we all must take account of other factors when correcting an image, not just the color of a single known object - this is a wil o' the wisp. One good way to do this is to use curves to set shadow, highlight, and neutral in the final image. --

Mike Russell
www.curvemeister.com
www.geigy.2y.net

bradadad

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studio gray's values