Seeking Violet

Started Jun 23, 2014 | Discussions thread
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xpatUSA Forum Pro • Posts: 11,056
Seeking Violet

My Sigma cameras are most reluctant to render violets properly. A shot of a CFL lamp spectrum certainly shows blue where violet should be. (I'm waiting for the sun to come out, to try it with my SD9 and a water hose.)

As opposed to this crop from a Googled Canon EOS-400D shot which, according to the meta-data, was processed with the GIMP:

Processing unknown but looks like increased saturation

On the other hand, the Foveon comes up with:

Output of several converters and one RAW composite image (bottom, left).

The apparent violet in the top right image is due to color clipping and should be ignored.

There are many hues and shades of 'violet' so, for this thread, I nominate a dominant wavelength of 436nm (a Mercury emission line) as being 'violet'. It is the second line from left in the above images.

I've found that the necessary preset color conversion matrices for my Foveon sensors kill this hue of violet. What I am seeking is a method of rendering violet as it should be, most likely at the expense of other colors' accuracy. My tool would a conversion utility which allows adjustment of a 3x3 simple conversion matrix (straight from RAW to RGB, far as I can tell).

Sun's coming out . . . I'm off to the water hose!


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 xpatUSA's gear list:xpatUSA's gear list
Sigma DP2s Sigma DP2 Merrill Panasonic Lumix DMC-G1 Sigma SD10 Sigma SD14 +14 more
Sigma SD9
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