New article on color management

Started Apr 26, 2013 | Discussions thread
xpatUSA Forum Pro • Posts: 13,455
Re: Camera-->sRGB versus Camera-->ProPhoto-->sRGB

gollywop wrote:

xpatUSA wrote:

gollywop wrote:

How does dcraw treat a raw file?  That would give us a good hint.

For what it's worth, dcraw offers the following -o (output) options:

Thanks, xpatUSA.  Yes, those are the choices for an output space.  So it would appear that XYZ is a possible output space, but it is not employed as a matter of course during processing, which is what I'd figure.  It's like RPP allows LAB as a choice for an output space, but it doesn't figure in any of the basic rendering operations.

My mistake. As I understand color theory, XYZ is a color model and, as you probably know, color spaces are contained within a color model. XYZ itself is, as it were, dimensionless - often normalized to 1,1,1 for example. What Coffin does (at least with my X3F's) is transform the 3-channel raw data into 16-bit XYZ numbers, i.e. 1 = 65,553. Theoretically, he should do this internally anyway, irrespective of the output space but he's not forced to do so and I don't know if he does. When displayed on the monitor, his XYZ images come out very unsaturated as one expect. One of Coffin's profiles is ProPhoto linear gamma, so I suspect that he may use Kodak RIMM/ROMM as the working area. ArvoJ probably knows more about that than I.

Similarly, CIELAB is also a color model, not a space, so I'm not sure how it could be chosen as an output space although it is most certainly a PCS for some profiles.

Er, what is RPP?

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