Hello Chris,
that's conclusive, I have nothing to add. Thanks for the elaborate
explanations!
This time I will not assert anything at all, just post a test case and
kindly ask for your (and of course, anybody else's) input on the test
case itself and the results.
Testing image: Linear gray ramp, Lab, 256 levels at 8bpc
http://hoech.net/files/Linear_Gray_Ramp_Lab.tif.zip
Tests and results (levels after conversion):
Converting (RI=perceptual, if not otherwise stated)...
to ECI-RGB v1: 225
to ECI-RGB v1 rel.col+bpc: 225
to ECI-RGB v1, then ISO Coated v2 (ECI): 224
to ECI-RGB v1, then ISO Coated v2 (ECI) rel.col.+bpc: 225
to 16bpc, then ECI-RGB v1, then ISO Coated v2 (ECI), then 8bpc: 256
to 16bpc, then ECI-RGB v1, then ISO Coated v2 (ECI) rel.col.+bpc, then
8bpc: 256
to ECI-RGB v1 with gamma=2.3: 236
to ECI-RGB v1 with gamma=2.3, then ISO Coated v2 (ECI): 235
to ECI-RGB v1 with gamma=2.3, then ISO Coated v2 (ECI) rel.col.+bpc: 236
to ECI-RGB v1 with gamma=2.4: 237
to ECI-RGB v1 with gamma=2.4, then ISO Coated v2 (ECI): 237
to ECI-RGB v1 with gamma=2.4, then ISO Coated v2 (ECI) rel.col.+bpc: 237
to ECI-RGB v1 with gamma=2.5: 236
to ECI-RGB v1 with gamma=2.5, then ISO Coated v2 (ECI): 236
to ECI-RGB v1 with gamma=2.5, then ISO Coated v2 (ECI) rel.col.+bpc: 236
to eciRGB v2: 256
to eciRGB v2 rel.col+bpc: 256
to eciRGB v2, then ISO Coated v2 (ECI): 256
to eciRGB v2, then ISO Coated v2 (ECI) rel.col.+bpc: 256
(regarding the tests with ECI-RGB v1 and custom gamma, I tested gamma
values 2.0 - 2.6 and then only included the results at the peak and
around, I hope that's ok)
Kind regards,
Florian Höch