4 Replies Latest reply on May 6, 2007 7:42 AM by (Barry_Clive_Pearson)

    Adjust color rendering for your camera in Camera Raw

      According to the help node with the above subject, one can embed profiles into TIFF, JPEG, PSD and DNG files and select them within Camera Raw 4.

      I can assign profiles to all excepto DNG files, since DNG files cannot be saved and thus cannot be persistently be assigned a profile (say created with ColorEyes 20/20 camera profiler software). How then can I assign a profile to a raw image? Is the help incorrect or mis-written?

      Thanks,
      Juan Dent
        • 1. Re: Adjust color rendering for your camera in Camera Raw
          michael shaffer Level 1
          > ... one can embed profiles into TIFF, JPEG, PSD and DNG files and select them within Camera Raw 4.

          It's inaccurate to imply that a color space is embedded into a DNG. A raw can be designated to open into PS while associated with a specific color space, and even the JPEGs, TIFs, or PSDs saved from ACR are embedded with the chosen color space ... however, the chosen color space will not necessarily be remembered the next time you work with the same raw file.

          To "embed a raw file with a color space" would imply that it need be "converted" to another color space when (for whatever reason) another is deemed appropriate. Of course, this isn't true because "conversion" implies the raw data would change, and ACR works with raw files non-destructively.

          HTH :)
          • 2. Re: Adjust color rendering for your camera in Camera Raw
            Level 1
            ACR does not use ICC camera profile (like one created with ColorEyes.) The method that Adobe (Thomas Knoll) has implemented to adjust for the color idiosyncracies of specific cameras is Calibration (in the Calibrate tab.)

            Capture One, BibblePro, and Raw Developer are a few raw converters that use ICC camera profiles.
            • 3. Re: Adjust color rendering for your camera in Camera Raw
              Level 1
              Changes introduced with DNG version 1.1.0.0 included new tags AsShotICCProfile (+ AsShotPreProfileMatrix) and CurrentICCProfile (+ CurrentPreProfileMatrix).

              If a camera or editor uses these, are the ColorMatrix1 (and if required ColorMatrix2) tags required to be present anyone, for example for ACR to use, while these xICCProfile tags are an optional alternative? How does it all fit together?

              AsShotICCProfile:
              "This tag contains an ICC profile that, in conjunction with the AsShotPreProfileMatrix tag, provides the camera manufacturer with a way to specify a default color rendering from camera color space coordinates (linear reference values) into the ICC profile connection space.
              "The ICC profile connection space is an output referred colorimetric space, whereas the other color calibration tags in DNG specify a conversion into a scene referred colorimetric space. This means that the rendering in this profile should include any desired tone and gamut mapping needed to convert between scene referred values and output referred values.
              "DNG readers that have their own tone and gamut mapping controls (such as Adobe Camera Raw) will probably ignore this tag pair".

              CurrentICCProfile:
              "This tag is used in conjunction with the CurrentPreProfileMatrix tag.
              "The CurrentICCProfile and CurrentPreProfileMatrix tags have the same purpose and usage as the AsShotICCProfile and AsShotPreProfileMatrix tag pair, except they are for use by raw file editors rather than camera manufacturers".
              • 4. Re: Adjust color rendering for your camera in Camera Raw
                Level 1
                > "The method that Adobe (Thomas Knoll) has implemented to adjust for the color idiosyncracies of specific cameras is Calibration (in the Calibrate tab.)"

                That is what is visible in ACR (and Lightroom).

                But the DNG specifications provide an additional feature for camera-specific variations, and in fact the DNG Converter uses it where it can deduce useful values from metadata within the original raw file.

                There are (optional) CameraCalibration1 and CameraCalibration2 values, which are multipliers for the normal ColorMatrix1 and ColorMatrix2, so the latter would be used as model-dependent values by a manufacturer, while the former would be camera-specific fine-tuning.

                That suggests that, in principle, if there were a way of identifying CameraCalibration1 and CameraCalibration2 for a specific camera, they could somehow be put into DNGs during conversion from the original raw files so that ACR or presumably ANY DNG-reader (even non-Adobe)would use them instead of the ACR (and Lightroom) specific camera calibration values. (?)