4 Replies Latest reply on Oct 6, 2008 10:43 AM by dorin_nicolaescu

    Camera profiles and Highlight Recovery: color shifts

    dorin_nicolaescu Level 5
      I often see significant hue shifts and loss of saturation when using the Recovery slider in conjunction with the new dng camera profiles. I don't remember to ever have this 'problem' with legacy ACR profiles. In the sample below, you can see just that:

      Sample: http://farm4.static.flickr.com/3224/2918603614_7a562db832_o.png

      This becomes a bit of a problem, as recovering highlights now brings color shifts as a side-effect and you have to go fiddling with color controls.

      Often, the new, 'shifted' colors are even more pleasing than the 'unshifted' (i.e. recovery set to zero), but this is a psychological and a workflow problem too. It is just not nice to know that controls are interdependent and have side-effects.

      Is it a bug or a fact of life? What's so different about the old a new profiles, that cause this difference in recovery effect?

      The DNG to play: http://www.yousendit.com/download/bVlBblFOR0Y3N0JFQlE9PQ
        • 1. Re: Camera profiles and Highlight Recovery: color shifts
          MadManChan2000 Adobe Employee
          Dorin, any change you make to the color profile means that any/all aspects of color rendering are subject to change, including in shadows, midtones, and highlights. The Camera Matching profiles tend to retain more color saturation in the highlights compared to the older profiles which generally push towards white in the highlights.
          • 2. Re: Camera profiles and Highlight Recovery: color shifts
            dorin_nicolaescu Level 5
            Eric, I was not talking about the color rendering with the CM profiles per se, but rather the effect that the Recovery slider has on colors when a CM profile is applied.

            > The Camera Matching profiles tend to retain more color saturation in the highlights compared to the older profiles which generally push towards white in the highlights.

            Yeas, right. That's by default. But look at my sample, and see what the colors turned into when I applied a Recovery of +20. I never experienced this with the old profiles.
            • 3. Re: Camera profiles and Highlight Recovery: color shifts
              MadManChan2000 Adobe Employee
              Dorin, the older matrix-based profiles produced the same hue across tonal ranges. The Camera Matching profiles generally do not (i.e., they contain hue twists as a function of lightness). This is why you will observe changes as you adjust the Exposure & Recovery sliders, compared to the older profiles (which were designed strictly with scene-referred colorimetry in mind).
              • 4. Re: Camera profiles and Highlight Recovery: color shifts
                dorin_nicolaescu Level 5
                Eric, thanks a lot for the explanation and technical details.

                Knowing this helps me a bit, as it confirms my observations. What is not clear, is how these shifts will/should (or would they?) be addressed?

                I mean Recovery was a perfect control until now. it just did what is should, reliably and consistently. Now we have the side-effect of color shifts.

                a) Will Adobe adjust the algorithm to fit the new profile system? A bad thing, because it will not assure backward compatibility.

                b) Will Adobe add a new control? Worse, because it adds unnecessary complexity.

                c) Will/could the profiles be modified in a way as these color shift don't happen. As I understand from your previous post, this doesn't seem possible.

                d) Will it just be left as is and I'll have to live with the color shifts? Now it seems it's the most likely option. Sad, because Recovery used to be so powerful, and now its power is somewhat compromised.