8 Replies Latest reply: Dec 14, 2011 11:07 AM by Geoff the kiwi RSS

    Lightroom 3.6 and DNG Profile Editor

    hkulokari Community Member

      After updating to LR 3.6, DNG Profile Editor does not display previews correctly, if base profile is one of the "new technology" camera specific profiles (for example the v4 profiles for Nikon). It looks like the previews are not properly converted to sRGB for display.

       

      I also noticed that if I decompile and then compile such a profile using dcptool of Chromasoft, the resulting profile generates very strange looking pictures.

       

       

      - Hannu

        • 1. Re: Lightroom 3.6 and DNG Profile Editor
          sandy_mc Community Member

          As regards dcpTool, can you give me some more details - exactly what profile you were converting, and what the command lines you were using to decompile and compile again?

           

          Sandy

          • 2. Re: Lightroom 3.6 and DNG Profile Editor
            hkulokari Community Member

            So far I have only tried Nikon D300 profiles, for example "Nikon D300 Camera Standard v4.dcp". And the command lines are of the form

             

            dcptool profilename.dcp test.xml

            dcptool -c test.xml newprofilename.dcp

             

            One would expect profilename.dcp and newprofilename.dcp to be equivalent. And until now they have been, otherwise dcptool would be useless.

             

            I guess there are in the new profiles some previously unused tags, which Lightroom and ACR understand but DNGPE and dcptool do not (yet). Hopefully those tags are documented in the DNG spec. DNG is an open standard, right?

             

            -Hannu

            • 3. Re: Lightroom 3.6 and DNG Profile Editor
              sandy_mc Community Member

              Those command lines should give an identical profile, and so far as I am aware, Adobe haven't changed the DNG spec. Or at least, if they have they're keeping very quiet about it(!)

               

              It may possibly be a bug in dcpTool - I'll do some checking and see - give me a few days.

               

              Sandy

              • 4. Re: Lightroom 3.6 and DNG Profile Editor
                MadManChan2000 Adobe Employee

                There are some new tags being used by the v4 profiles.  We are working on a corresponding spec and SDK update.

                • 5. Re: Lightroom 3.6 and DNG Profile Editor
                  hkulokari Community Member

                  More food for thought:

                   

                  Besides Lightroom and some Nikon DSLRs, I also have PSE9, CS4+ACR 5.6 and a Nikon 1 V1, which was unsupported until LR 3.6 / ACR 6.6. Now, after the new camera profiles have been installed (they are common to all Adobe products), PSE9 and ACR5.6 both recognize Nikon 1. As they should. But camera specific profiles produce strange looking images. Same thing with v4 Nikon DSLR profiles. Adobe standard is fine.

                   

                  My conclusion is that there is some secret sauce in those new profiles, recipe so far known only to new LR and ACR. Open standard?

                   

                  And dcptool cannot fully decompile a profile, it only shows those parts it knows of. I think.

                   

                  Just idle curiosity on my part, I like Adobe Standard. But it would be nice to know the facts.

                   

                  -Hannu

                  • 6. Re: Lightroom 3.6 and DNG Profile Editor
                    MadManChan2000 Adobe Employee

                    As I have written above, there are some new tags in the v4 profiles, and we are working on a spec and SDK update.

                    • 7. Re: Lightroom 3.6 and DNG Profile Editor
                      sandy_mc Community Member

                      Yes, well, there are indeed new tags. Notably the following, from exiftool:

                       

                      Exif 0xc7a4                     : 1

                      Exif 0xc7a5                     : -0.5

                      Exif 0xc7a6                     : 1

                       

                      I'd guess these are offsets to the curves, or something similar, to get round posterization issues. That's consistent with what a V4 profile stripped of the new tags does, which is basically to overexpose.

                       

                      However, the bad news is, until Adobe publish a new version of the SDK and documentation, dcpTool will remain broken for V4 profiles. I'll try to do an update of dcpTool once the new SDK is out. Well, soon after anyway - getting the SDK and the XMP toolkit to compile is always a nightmare.

                       

                      Sandy

                      • 8. Re: Lightroom 3.6 and DNG Profile Editor
                        Geoff the kiwi CommunityMVP

                        Thanks team for the info.