Archives for October 2014

In the previous post, I reported on the location of the worst errors that resulted from taking this 8-bit sRGB image: and converting it to Adobe (1998) RGB and back many times, using double precision floating point precision for the intermediate calculations, and quantizing the result to 8 bit per color plane unsigned integers after… [Read More]

Yesterday I reported on the color errors generated when 8, 15, and 16 bit-per-color-plane images were converted from sRGB to Sdobe (1998) RGB and back many times, with color conversion calculations performed in double precision floating point, and quantizing to the original precision after every conversion. We found that 8 bit precision produced worst case… [Read More]

I took the 256 megapixel, 16-bit per color plane image filled with uniformly-distributed random colors that I used for the previous post, and performed iterative color space conversions in Matlab from sRGB to Adode (1998) RGB and back, measuring the errors in CIELab Delta E after each round trip. Because the image was so large,… [Read More]

It occurred to me that, what with CIEL*a*b* being the reference standard for the ICC color management scheme, that there might be some bias towards minimizing errors measured in Lab built into the Photoshop/ACE  algorithms. Lab is not perceptually uniform, although it tries hard, so things might be worse than they seem when Lab DeltaE is… [Read More]

We got pretty good results with round trip conversions from sRGB to Adobe RGB and back using a smallish 16-bit image and a 16-bit image with all the 8-bit sRGB colors. Before I declare victory, I decided to see what happened with a lot more 16-bit colors. I wrote a Matlab script to generate a… [Read More]