Originally posted by Lowell Goudge One thing I have learned is that no image is worth deleting, and In general, the best lessons come out of mistakes
I agree.
the variations you are seeing in the colour channels can be attributed to Noise as well as what is called metamerism - not all the colour filters used in the bayer array transmit 100% of the light that goes through them. Often the red channel is often one of the most problematic because of Infrared light contamination - because Silicon has a surprisingly high sensitivity to IR - but it isn't as sensitive to Blue and Ultraviolet wavelengths* and there is the strong Green component in sunlight** so a balance has to be struck. A perfect sensor with linear response to visible light coupled with a perfect bayer filter would render middle grey as
R=128
G=128
B=128. But AFAIK such a sensor has yet to be made - at least on a commercial scale. And that is why professional photographers use colour calibration software and hardware so these metameric errors can be corrected or controlled.
*which is why Foveon CCD sensors often have such weak blue sensitivity.
**arguably the most common light source