New article on color management

Started Apr 26, 2013 | Discussions thread
Detail Man
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Re: Does Melissa "Gloss Over" Image Noise ?
In reply to gollywop, Apr 27, 2013

gollywop wrote:

Detail Man wrote:

gollywop wrote:

Detail Man wrote:

gollywop wrote:

They are what they are, and as long as they are converted meaningfully into the output space, it doesn't make too much difference how they're used as a working space.

But that is precisiely the point being made - that the "Melissa" preview display, histograms, and color values reflect sRGB (tone-level) values only - and do not reflect ProPhoto RGB or Adobe RGB.

I would assume that the ProPhoto RGB output space is legitimately ProPhoto RGB.

In terms of color-gamut, yes. In terms of preview appearance, histograms, and color values, no.

But, isn't this only as a working space?  If so, that's not great, but it's not the same as saying that the conversion on "export" is not to a proper ProPhoto RGB output space.  Is that what you're saying?

What I am saying is that the Adobe CR and LR preview displays, histograms, and color value readouts (which are provided using "Melissa RGB") do not (within the linearized low-level region of sRGB and Melissa RGB) accurately correspond (in terms of RGB tone-levels) to what will actually exist if/when the in-process image is then rendered into ProPhoto RGB or Adobe RGB 1998 (but not sRGB).

That could very well be the case.  I'm not sure why they would be doing that.

Clearly, it has involved a conscious decision on Adobe's part to specifically proceed in that manner.

It is clear that the monitor rendering and histograms would have to be "gamma-ed" from the underlying linearized ProPhoto RGB, but it's not clear why it shouldn't properly reflect that working space.

Probably so that the preview displays would appear to have a consistency in appearance regardless of the chosen working (and the chosen output) color-spaces (in the case of CR, where the user does have a choice of working color-space, that is). Thus, they chose the lowest common denominator of sRGB (which also happens to provide the "rosiest" view where it comes to low-level image-noise).

The LR interface was likely kept the same in order to maintain operational consistency with CR.

What would obviously make the most sense would be to apply the particular gamma-correction that corresponds to the user's chosen output color-space, so that what the user sees accurately represents what the user is actually going to get upon output. The histogram displays and reported RGB tone-level values are arguably a less critical (though not at all undesirable) thing to get right where it comes to what represents the lowest typically visible EV on the preview display screen.

They (probably) have shied away from that because users might likely not be aware of that particular operational functionality, and then become frustrated when they (later) realize that their (albeit accurate) previewing depends upon "developing" for a given output color-space. Probably a rigor that they may (reasonably) assume surpasses the desire of (most) users ?

I can't say that the issue has ever caused me any particular problems -- but that's really beside the point.

I would not say so. If it is not something that (most) users notice, then why should they care ?

It would be an even worse situation if the output spaces were not accurate, but I don't believe that's the case.

Right. But the preview display appearance, histograms, and RGB tone-values are not accurate.

Meanwhile, I get the feeling that ACR, for all the time it has been with us, is still trying to get its feet on the ground.  But they do seem to be making progress.  The current version is a far cry better than what was around even one version past.

Adobe being such a new, small company (in sales and personnel), they do deserve our patience.

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