ICEpdf
  1. ICEpdf
  2. PDF-39

Colors in ICEpdf differ slightly from those of Abode

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Duplicate
    • Affects Version/s: 3.0, 4.0.1
    • Fix Version/s: 4.1.3
    • Component/s: Core/Parsing
    • Labels:
      None
    • Environment:
      ICEpdf 2.7.1

      Description

      The main text of the document is using cmyk and when using the alternative2 ->
      rgb algorithm is a pretty close match to what adobe is generating. However the
      Images uses an indexed cmyk colour space which seem to map correctly however we
      see heavy greens on some of the images. I've done some tracing and can't find
      anything that is out of place.

      I suspect there is something incorrect in how we apply the colour profile when
      building the image in Stream.makeImageWithRasterFromBytes.
      1. 7226.pdf
        494 kB
        Tyler Johnson

        Activity

        Hide
        Mark Collette added a comment -

        The Stream class has its own CMYK -> RGB conversion algorithm, which we could try replacing with Patrick's alternative2 algorithm. The existing algorithm is not an actual spec one, but is derived from a spec, but modified because certain CMYK image PDF cases were quite different in the brightness/lightness. Potentially there might be some gamma value or rendering intent that should be used to affect the CMYK conversion.

        Show
        Mark Collette added a comment - The Stream class has its own CMYK -> RGB conversion algorithm, which we could try replacing with Patrick's alternative2 algorithm. The existing algorithm is not an actual spec one, but is derived from a spec, but modified because certain CMYK image PDF cases were quite different in the brightness/lightness. Potentially there might be some gamma value or rendering intent that should be used to affect the CMYK conversion.
        Hide
        Patrick Corless added a comment -

        This issue was actually more related to CYYK to RGB. Some work was done on this issue for 4.1.3 for a client patch. This is a very difficult task to get correct as there is some colour loss when going from a subtractive to an additive colour model.

        Duplicate of PDF-247

        Show
        Patrick Corless added a comment - This issue was actually more related to CYYK to RGB. Some work was done on this issue for 4.1.3 for a client patch. This is a very difficult task to get correct as there is some colour loss when going from a subtractive to an additive colour model. Duplicate of PDF-247

          People

          • Assignee:
            Patrick Corless
            Reporter:
            Tyler Johnson
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            Dates

            • Created:
              Updated:
              Resolved: