Digital Camera RGB color space

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I need to generate some test scenes for color printer evaluations. Of course, there are many options.

One of these is to capture the scene with a digital camera and use those RGB values to describe the scene. These values are relatable to the scene, but modified by the spectral sensitivities of the camera and the camera manufacturerer's ideas of the best RGB values I should get.

Does anyone out there in the digital camera community (e.g., Kodak, Fuji, Questra, Olympus, etc.) know how, specifically, the internal RGB values of different cameras are modified: 1. By tonal corrections, e.g., toe, shoulder, overall gamma? 2. By a matrix, 3-D LUT or other complex function?

I know we could find out by photographing Munsell originals and backing out (reverse engineering) the tonal and color corrections, but you have to buy the camera first, and they're costly ....

Also, if an ICC profile is associated with the camera, what is it's reference color space? E.g., the CIELAB values of the original scene?

Thanks

-- William Kay (367561@home.com), January 07, 2000

Answers

Why not get a digitized copy of a Kodak Q-60 reference image and use that as a comparison. Standardized image, colour values are known, no other variables. Saves you the extra step of fighting with a digital camera image, that probably will not have the tonal range that you would get with the reference slide

Jonathan

-- Jonathan Ratzlaff (jonathanr@clrtech.bc.ca), January 08, 2000.


Why bother with a camera at all?

Surely colour swatches, greyscales and resolution bars can all be generated from Photoshop with absolute certainty about relative RGB values?

How to eliminate the variations in the "corrections" applied by different printer drivers, batch to batch variations in ink, and compatibility problems between different papers, inks and printers is altogether a more ticklish problem.

Good Luck,

-- Pete Andrews (p.l.andrews@bham.ac.uk), January 10, 2000.


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