ICEpdf
  1. ICEpdf
  2. PDF-475

CMYK colour conversion is a little dark

          Details

          • Type: Bug Bug
          • Status: Closed
          • Priority: Major Major
          • Resolution: Fixed
          • Affects Version/s: 4.3.3
          • Fix Version/s: 4.3.4
          • Component/s: Core/Parsing
          • Labels:
            None
          • Environment:
            any

            Description


            The sample PDF renders without error but the green back ground is quite a bit darker then what acrobat renders. The PDF uses a fairly complex colour model but after double checking the logic I think we are looking at a standard issues with CMYK to RGB colour conversion. The conversion process tends to generate darking colours then adobe.

              

              Activity

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              Migration created issue -
              Repository Revision Date User Message
              ICEsoft Public SVN Repository #31140 Thu Sep 27 09:44:30 MDT 2012 patrick.corless PDF-475 update the colour conversion calculation to match what we are doing in the Stream class. Basic change is to reduct the amount of black /y value during the conversion by a third.
              Files Changed
              Commit graph MODIFY /icepdf/branches/icepdf-4.3.3/icepdf/core/src/org/icepdf/core/pobjects/graphics/DeviceCMYK.java
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              Patrick Corless added a comment - - edited

              Update the DeviceCMYK conversion logic to match what we are doing in the stream class for image conversion. The basic idea behind the conversion tweak is to reduce the black or Y by about a third to give a better overall colour conversion to rgb.

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              Patrick Corless added a comment - - edited Update the DeviceCMYK conversion logic to match what we are doing in the stream class for image conversion. The basic idea behind the conversion tweak is to reduce the black or Y by about a third to give a better overall colour conversion to rgb.
              Repository Revision Date User Message
              ICEsoft Public SVN Repository #31384 Wed Oct 10 11:13:46 MDT 2012 patrick.corless PDF-475 update the colour conversion calculation to match what we are doing in the Stream class. Tweaked it again to ignore an all black colour as teh lighting was causing content to be painted as white.
              Files Changed
              Commit graph MODIFY /icepdf/branches/icepdf-4.3.3/icepdf/core/src/org/icepdf/core/pobjects/graphics/DeviceCMYK.java
              Repository Revision Date User Message
              ICEsoft Public SVN Repository #31432 Thu Oct 11 15:12:06 MDT 2012 patrick.corless PDF-475 updated black reduction ratio to be shared between the stream class and this. Also only reduce black if there are other cmy colour components. An new system property org.icepdf.core.color.cmyk.black (3.0 default or black/3.0) can be used to tweak blacks if needed.
              Files Changed
              Commit graph MODIFY /icepdf/branches/icepdf-4.3.3/icepdf/core/src/org/icepdf/core/pobjects/graphics/DeviceCMYK.java
              Commit graph MODIFY /icepdf/branches/icepdf-4.3.3/icepdf/core/src/org/icepdf/core/pobjects/Stream.java
              Migration made changes -
              Field Original Value New Value
              Reporter Migration [ remote ] Patrick Corless [ patrick.corless ]
              Migration made changes -
              Status Open [ 1 ] Resolved [ 5 ]
              Resolution Fixed [ 1 ]
              Migration made changes -
              Fix Version/s 4.3.4 [ 10341 ]
              Patrick Corless made changes -
              Status Resolved [ 5 ] Closed [ 6 ]

                People

                • Assignee:
                  Patrick Corless
                  Reporter:
                  Patrick Corless
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                  Dates

                  • Created:
                    Updated:
                    Resolved: