![]() is rendered in a pink/magenta color rather than white it usually means that the white level constant is too high.If you open an image with a large clipped area and that single value regardless of color channel, ISO or aperture.dcraw provides the default values used by RawTherapee, but often provides too high white levels, and only provides a.RawTherapee’s camconst.json file has interesting information on this: Beep6581/RawTherapee/blob/dev/rtengine/camconst.json#L113 In addition, the pixel values appear to have been scaled (in camera or during decompression) because the histogram has more or less evenly spaced gaps (every 6th or 7th value has zero samples for red and blue, and every 40th value for green) irrelevant but annoying.Ĭome to think of it, this was the rabbit hole I tried to avoid… The white level listed is 15892 while dcraw tiff has all saturated pixels at 16383. There are of course other mysteries in Adobe Dng Converter processed. I think I need to look into the ICC profile linked by rom9 in ‘Any interest in a “film negative” feature in RT?’ (post #177) and see if I can extract something from there. Now, the matrix values are most likely wrong because the color separations effectively takes the camera color space out of the equation. As for their values, the white balance (‘as shot neutral’ I believe) will be very close to 1,1,1 (I control R, G, and B exposures), the black subtraction levels from camera are per CFA channel but identical in value so one value is probably enough, and the ColorMatrix2 (produced by Adobe Dng Converter) is identical to the one you listed. The three tags you mentioned are already included in makeDNG. In dcraw, this is invoked with -h what it does is to make a RGB image half the size of the original, with each 2x2 quad of pixels used to make a single RGB pixel, with the original measurements of the quad. These numbers need to be divided by 10000.0 to produce the float numbers needed in the DNG tag.īTW, if you are going through the channel separation to retain the original measurements in constructing the RGB pixels, you might investigate just using the ‘half’ demosaic algorithm. There’s probably more to this needed to support your workflow, but it should get you going. I snarfed the D7200 numbers from RT’s camconst.json file for you: ![]() In a DNG, those would be stored in one of the ColorMatrix tags, the one to which the corresponding CameraCalibration tag is assigned “D65”. The raw processor probably already has suitable numbers, but it probably won’t assign them to TIFFs. ![]() This is the 3x3 matrix used to convert the raw image from camera colorspace to whatever next colorspace you desire. For Nikon, I think it should be a single value, but some cameras deliver a number for each channel in the bayer or xtrans array.
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