9 Replies Latest reply: Aug 7, 2011 5:21 PM by ssprengel RSS

    LR3 JPEG/DNG Metadata Confusion

    Reg2233 Community Member

      Hi,

      I'm a little confused about XMP data and the LR3 catalog itself.

       

      First, I understand that DNG files can have embedded keywords and other metadata -- and 95% of my files are CR2 files that I bring into LR3 as DNGs and keep them as DNGs.  So I am NOT using raw files with sidecar files.

       

      But where I'm confused is the "automatically write changes into XMP" LR3 catalog option and how it relates to JPEG files.

       

      I was of the understanding that if I make changes in the develop module (eg. contrast)  to a JPEG file (not a DNG), then these changes will NOT be saved to the original JPEG file, but will be "recorded" in the LR3 catalog.

       

      But now If I allow LR3 to "automatically write changes into XMP"  -- will this WRITE these develop module changes (e.g. the contrast change)  to the original JPEG?  Or does the "automatically write changes into XMP" only refer to the keywords and other metadata in a JPEG file?

       

      Thanks for any help in clearing this up,

      R

        • 1. Re: LR3 JPEG/DNG Metadata Confusion
          DdeGannes MVP

          LR by default writes all your work with imported files to the Catalog. If checked "Auto write changes to XMP" will also create a side car for raw files, for DNG, TIFF, JPEG etc the XMP data will be stored within the file itself.

          • 2. Re: LR3 JPEG/DNG Metadata Confusion
            thedigitaldog ACP/MVPs

            Reg2233 wrote:

             

             

            But now If I allow LR3 to "automatically write changes into XMP"  -- will this WRITE these develop module changes (e.g. the contrast change)  to the original JPEG? 

            You only write the instructions, not the rendering with Auto write XMP (or command/control S in a manual fashion). So if you open such a document in say Photoshop, you will NOT see the color any differently than before you wrote those metadata edits. You have to actually render out an iteration (a new JPG in this case) to see the edits applied in the new document.

            • 3. Re: LR3 JPEG/DNG Metadata Confusion
              b_gossweiler Community Member

              R,

               

              In  both cases (DNG and JPEG), LR - if instructed so by "automatically write ..." or Ctrl-S - writes metadata into the so called XMP section of the appropriate files, and does not alter the image data itself.

               

              In the case of a DNG, this written data includes metadata such as keywords, title, caption etc. as well as develop settings.

               

              In the case of a JPEG, this includes metadata such as keywords, title, caption etc., and develop settings only if "Include Develop settings in metadata inside JPEG, TIFF, and PSD files" is checked in the catalog settings.

               

              The develop settings written into the XMP section can only be seen if you open the image with a tool that recognizes and interpets this data, i.e. open in PS/PSE via ACR or a re-import into LR.

               

              Beat

              • 4. Re: LR3 JPEG/DNG Metadata Confusion
                ssprengel MVP

                You would see the effect of the XMP data in the JPG if your PS is new enough and you have PS set to use ACR on the way in for JPG files that either have settings or always, but you see those changes because PS has called on ACR to render them, not because they are in rendered into the file, already.

                • 5. Re: LR3 JPEG/DNG Metadata Confusion
                  Jeff Schewe Community Member

                  thedigitaldog wrote:

                   

                  So if you open such a document in say Photoshop, you will NOT see the color any differently than before you wrote those metadata edits. You have to actually render out an iteration (a new JPG in this case) to see the edits applied in the new document.

                   

                  Actually, if you write the xmp adjustments into a JPEG, I'm pretty sure Bridge will see them (if you have the ACR Prefs set to open JPEGs with settings) and you can always open the JPEG using Camera Raw which deffinately will see the adjustments if the ACR prefs are set to use Camera Raw to open JPEGs with settings.

                  • 6. Re: LR3 JPEG/DNG Metadata Confusion
                    thedigitaldog ACP/MVPs

                    Yes of course ACR will see the adjustments and provide you a ‘correct’ preview but Photoshop will not. I might have to try Bridge (I generally don’t use it at all).

                    • 7. Re: LR3 JPEG/DNG Metadata Confusion
                      Reg2233 Community Member

                      So just so I have this correct with JPEGs:

                       

                      1, If I make changes in LR3 to a JPEG (e.g. contrast), this contrast change is saved in the LR3 catalog.

                       

                      2. I can ADDITIONALLY save metadata (keywords, etc)  in XMP data into a JPEG if I have the "automatically write xmp." settings checked or if I save it manually to the file

                       

                      3. I can ADDITIONALLY save the develop settings (e.g. the contrast change I made in #1) by including the develop data in the JPEG in the same dialogue box.

                       

                       

                      But now if I opened this keyword, added contrast-adjusted JPEG in another program,  only "XMP-aware" programs would allow me to see these keywords and contrast changes.  Is this a correct assessment?

                       

                      And lastly, if I do save the develop settings to the JPEG itself, doesn't that violate the "non-destructive" editing concept of LR3?

                       

                      Thanks again!

                      • 8. Re: LR3 JPEG/DNG Metadata Confusion
                        Jeff Schewe Community Member

                        Reg2233 wrote:

                         

                        But now if I opened this keyword, added contrast-adjusted JPEG in another program,  only "XMP-aware" programs would allow me to see these keywords and contrast changes.  Is this a correct assessment?

                         

                        Yeah, pretty much...but the key is how you've set the Camera Raw prefs...

                        • 9. Re: LR3 JPEG/DNG Metadata Confusion
                          ssprengel MVP

                          The IMAGE DATA is not affected when you write XMP settings to it.  That is what is being referred to by non-destructive...you're not changing the image data of the JPG, just adding extra things to the headers that are not part of the image.