15 Replies Latest reply on Aug 1, 2016 3:58 PM by thedigitaldog

    JPG to DNG?

    Vic-86 Level 1

      Is there any advantage to converting jpgs to dng. I know it will not improve the quality of the image and that the file size will increase. But is there anything that would improve, like editing capability? Or is it just a wash and don't bother?

       

      Thanks

        • 1. Re: JPG to DNG?
          dj_paige Level 9

          I know some people claim there is a benefit to converting JPGs to DNG, but really you have no increased editing ability with a DNG. The entire process to me seems like a waste of time and a waste of disk space.

          • 2. Re: JPG to DNG?
            john beardsworth Adobe Community Professional & MVP

            The advantage is that DNG prevents any possibility of opening a jpg in Photoshop and saving your edits back to the original.

            • 3. Re: JPG to DNG?
              MichelBParis Adobe Community Professional & MVP

              dj_paige wrote:

               

              I know some people claim there is a benefit to converting JPGs to DNG, but really you have no increased editing ability with a DNG.

              Other possible reasons:

              Enable JPG conversion for DNG Converter | Photoshop Family Customer Community

              The entire process to me seems like a waste of time and a waste of disk space.

              With Lightroom, I tend to agree.

              In my context (Elements organizer) converting to DNG solves many problems when editing jpegs in ACR... but that's not the purpose of the Lightroom forum .

              The waste of disk space is far less significant than for heavy raw files.

              • 4. Re: JPG to DNG?
                Vic-86 Level 1

                Lightroom uses the same engine as ACR. So what advantages do you gain in ACR. I think they would apply to Lightroom, no?

                • 5. Re: JPG to DNG?
                  dj_paige Level 9

                  If you're starting from Photoshop Elements, you have to use ACR.

                   

                  There are no advantages using ACR if you are starting from Lightroom.

                  • 6. Re: JPG to DNG?
                    99jon Adobe Community Professional & MVP

                    Is there any advantage to converting jpgs to dng

                    Yes. Try it.

                    • 7. Re: JPG to DNG?
                      Vic-86 Level 1

                      OK, I must be missing something, let me see if I understand. Bear with me and stop me where I go off track.

                      Earlier you stated that there "converting to DNG solves many problems when editing jpegs in ACR".

                      At that point you would be opening a DNG file in ACR, rather than a JPG. Is that correct?

                      If both of these things are true then there is an advantage to converting to DNG for editing in ACR.

                      Since Lightroom uses ACR, with a different interface, would the advantages of opening a converted file in Lightroom not be the same as those of opening the same converted file in ACR?

                      And finally, what are the advantages of opening a JPG converted to DNG in ACR, or should I post the question in a different forum?

                      Thank you

                      • 8. Re: JPG to DNG?
                        thedigitaldog MVP & Adobe Community Professional

                        There's no advantage! DNG is a container you've placed the JPEG data into. It's still JPEG data.

                        • 9. Re: JPG to DNG?
                          dj_paige Level 9

                          OK, I must be missing something, let me see if I understand. Bear with me and stop me where I go off track.

                          Earlier you stated that there "converting to DNG solves many problems when editing jpegs in ACR".

                          I most certainly never said anything like that. Especially in a Lightroom forum, we are talking about Lightroom, where converting JPGs to DNGs solves very few problems.

                           

                          MichelBParis said that, starting from Elements, not Lightroom he feels that converting to DNG solves many problems.

                           

                          At that point you would be opening a DNG file in ACR, rather than a JPG. Is that correct?

                          If both of these things are true then there is an advantage to converting to DNG for editing in ACR.

                          NOOOO! Not if you are starting from Lightroom. We are talking about Lightroom, aren't we? If we are talking about starting from Lightroom, there is only a very tiny benefit of converting JPGs to DNG, as mentioned by John Beardsworth, and quite honestly, I'm not aware of anyone actually having the problem of accidentally overwriting their JPGs from Photoshop starting in Lightroom.

                           

                          Hey Vic-86, read carefully. You have misunderstood the entire thread.

                          • 10. Re: JPG to DNG?
                            Vic-86 Level 1

                            OK, I'll try it again. I didn't see anything in quick pass into the Develop module after converting.

                            Would you mind telling me what you've found to be advantages?

                             

                            Thank you

                            • 11. Re: JPG to DNG?
                              99jon Adobe Community Professional & MVP

                              DNG provides a container against future degradation. Like tiff (or avi in Video) the container provides greater protection than an original jpeg witch can be degraded by editing or simple rotation.

                              • 12. Re: JPG to DNG?
                                thedigitaldog MVP & Adobe Community Professional

                                99jon wrote:

                                 

                                DNG provides a container against future degradation. Like tiff (or avi in Video) the container provides greater protection than an original jpeg witch can be degraded by editing or simple rotation.

                                I don't believe that's true. Depends on the edits and where.

                                If you're creating parametric edits, in LR or ACR, you're just embedding those instructions into the container; JPEG or DNG or TIFF.

                                Now if you apply pixel based edits in Photoshop, sure.

                                If you create parametric edits in ACR or LR, the edits do not appear in the JPEG until you render that into a new iteration and then yes, the JPEG edits are applied to that data and yes, you'll undergo degradation.

                                Open a JPEG in ACR as an example, apply an edit and click "Done". You don't see the edit in Photoshop proper. They do exist in the JPEG container like editing a TIFF the same way. Do this again but instead of "Done" click "Open" which tells ACR, render the edits into the pixels. You see the edits in PS proper and the damage so to speak, is done. The edits were applied to the pixels.

                                What John wrote (The advantage is that DNG prevents any possibility of opening a jpg in Photoshop and saving your edits back to the original.) kind of proves that point.

                                • 13. Re: JPG to DNG?
                                  Vic-86 Level 1

                                  Thank you

                                  • 14. Re: JPG to DNG?
                                    Vic-86 Level 1

                                    Actually since I started the thread I think its more likely that you misunderstood. It apparent that there is no hope of resolving the question, but I thank 99jon and thedigitaldogfor understanding the question and replying with, what I assume, they have experienced in this regard.

                                    Bye

                                    • 15. Re: JPG to DNG?
                                      thedigitaldog MVP & Adobe Community Professional

                                      It's actually pretty easy to prove that the parametric instructions embedded into a JPEG do not alter it pixel wise.

                                       

                                      1. Start with any JPEG. Duplicate it in the Finder so you have two copies that are identical.
                                      2. Setup ACR to support this format for editing.
                                      3. Open the 1st JPEG and apply a very radical edit in ACR (I move the WB way off as well as exposure).
                                      4. Click Done, NOT Open.
                                      5. Turn OFF ACR support for JPEG.
                                      6. Open each in JPEG Photoshop. You now have one JPEG that wasn't touched and a 2nd that had a parametric edit. Note that both appear identical.

                                      I used Apply Image command** to subtract the one from the other. They are identical.

                                      Conclusion: JPEG edits from ACR and LR do not alter the pixel data so there's no degradation in either the edit or re-saving a JPEG over again with such parametric edits. So converting it to DNG buys you nothing! IF you're producing parametric edits using ACR or LR.

                                       

                                      ** http://digitaldog.net/files/Apply_Image.pdf