Hi All,
I’m the mysterious stranger that emailed @Elle the other day about her sRGB profile and its 4096-point TRC. She pointed me to this thread, and I thought I’d chime in with some info that might be helpful.
The reason I had emailed her was that I was doing some research into point-based TRC accuracy, and I had found that the 4096-point curve in her V2 sRGB profile was less accurate than the 1024-point curve used in most other profiles, particularly in the linear section of the curve at its start. I’ve published that research here: Making a Minimal sRGB ICC Profile Part 2: Curve the Curves - PhotoSauce Blog
My next step is to do some comparisons with profiles I’ve created to normalize all settings except the curve, so I can see what kind of real-world impact the curve accuracy has. The worst-case scenario I could come up with was a conversion from sRGB to something with a much wider gamut, like ProPhoto, which would move the individual colors the furthest. I can compare output when converting from a reference V4 pfofile with the output from V2 profiles with various curve definitions. My initial tests were done using the LCMS tifficc util, and so far, they confirm what I found with my earlier mathematical analysis.
I’m wondering, though, whether there are some implementation details in LCMS that might give bad results or whether there’s something else that has a known better implementation. If anyone knows a better way to test, I’d be most appreciative.