Basic colourspace question:
What is the best colourspace for getting the best out of an Epson 7900/Colorburst/CS4/Phocus/H3D11-50?
I have been told that DCAM is the best - and when I asked which DCAM?, I was told that I had to spend a day learning how to analyze each picture to work out which colour space to use?
Even if you don't use Joseph Holmes' DCAM spaces, you can learn quite a bit about color spaces and their application by reading the essays on his web site
His section Gamut Plots
compares them to aRGB and ProPhotoRGB. He is concerned about matching the gamut of the image to that of the space to avoid quantization errors, but admits that these can largely be eliminated by using a bit depth of 16. He points out that aRGB uses a reference white of D65, whereas the PCS (profile connection space) used for most color management is D50. With aRGB one may get errors from chromatic adaption. Also, the gamut is aRGB is not sufficient for some modern printers. ProPhotoRGB uses D50 and is wide gamut, but has a gamma tone curve, which he says becomes too flat near black and is not perceptually uniform. His curves have a perceptually uniform tone curve (i.e. basically L*). Again, this deficiency is largely eliminated at a bit depth of 16.Bruce Lindbloom
discusses these considerations in his proposal for a new color space, BetaRGB. It uses a reference white of D50 and a 2.2 gamma tone curve. To minimize quantization errors, he chose color primaries that include most real world colors. The gamut is not as wide as ProPhotoRGB. He states that a gamma of 2.2 produces smaller ΔEs than the gamma of 1.8 used in ProPhotoRGB. Again if one uses a bit depth of 16, this is likely not significant.
Spaces using an L* tone curve are available, for example eciRGB_V2
. It is widely used in Europe, but has not caught on in the USA. I think that the ISO22028-2_ROMM-RGB.icc profile is essentially an updated ProPhotoRGB, but it does not appear to be in widespread use.
In view of the above discussion, I would conclude that 16 bit ProPhotoRGB is the most suitable widely used space for use with wide gamut printers such as your Epson.