18 Replies Latest reply on Jun 16, 2017 6:00 AM by Alberto_aa

    Disable compression seems not to work

    Alberto_aa

      Hello,

      I was experimenting with compression of psd and psb files but it seems not to work (Photoshop CC2017.1.1).

      My aim is to monitor performances while opening/saving a 2.9GB psb on SSD and HDD.

       

      Unfortunately disabling compression seems not to work, indeed the file saved without compression is the exact same size of the one saved with compression (already tried not maximizing compatibility).

       

      So far my findings with compression on are as expected, the two drives have nearly the same timing:

      Compression enabled1xSSD1xHDD2xSSD2xHDD3xSSD3xHDD
      open (s)10.211.810.610.410.210.4
      save (s)14.117.313.814.313.814.2

       

      is there a way to effectively disable the compression?

      I tried checking disable and reopen Photoshop but still not working.

       

      Message was edited by: Alberto Bua - added PS version.

        • 1. Re: Disable compression seems not to work
          Benjamin Root MVP & Adobe Community Professional

          Why not try Tiff?

          • 2. Re: Disable compression seems not to work
            Alberto_aa Level 1

            Because I would like the setting to works

            • 3. Re: Disable compression seems not to work
              Benjamin Root MVP & Adobe Community Professional

              Of course - I meant only for your testing.

               

              Just got back to my workstation and gave compressed/uncompressed PSD a try. The compressed PSD took longer to save, so I figured it had worked.  Sure enough, it had - compressed: 565,220K; uncompressed: 960,549K. See here:

               

              1.jpg

               

              So now I must ask for further details on your testing process. Did you simply change the setting under Edit > Preferences > File Handling and save...or did you change settings, restart PS, rebuild file, save? The latter is what you should do.

               

              I am also running PS CC 2017.1.1 (4/25/17 build) There is an update over in the CC app I've not installed yet. I'll update and try again to be sure.

              • 4. Re: Disable compression seems not to work
                Alberto_aa Level 1

                That's so strange. I'm not able to make it works.

                Tried everything you said, i.e.: change the setting, restart PS, rebuild the file, save the file.

                The resulting file size is exactly the same hence opening/saving have the same timings.

                 

                I've the same build as yours: Adobe Photoshop Version: 2017.1.1 20170425.r.252 2017/04/25:23:00:00 CL 1113967  x64

                • 5. Re: Disable compression seems not to work
                  davescm Adobe Community Professional

                  I wonder if this is something in the files. I also tried this and got identical results to the original poster i.e. no change in file size. That wasin both CC2017 and CS6. I will try variations on the image mode and content later this evening.

                  Dave

                  • 6. Re: Disable compression seems not to work
                    Benjamin Root MVP & Adobe Community Professional

                    Hmm, that is very interesting. By the way, are you on Mac or Win? You could try a preference reset.

                     

                    Win: Press and hold Ctrl+Alt+Shift immediately after initiating Photoshop's startup. A box will appear asking if you want to continue with the reset, select "yes." If you don't see this, you weren't fast enough...Try again.

                     

                    Mac: Press and hold Cmd+Opt+Shift then start Photoshop. A box will appear, asking if you want to continue with the reset, select "yes."

                    • 7. Re: Disable compression seems not to work
                      Benjamin Root MVP & Adobe Community Professional

                      I wonder if this is something in the files. I also tried this and got identical results to the original poster i.e. no change in file size. That wasin both CC2017 and CS6. I will try variations on the image mode and content later this evening.

                      That could be. I used five layers with a Hard Light blend mode and three adjustment layers. Also, 16 bit and ProPhoto RGB. Both files were 100% identical except compression

                      • 8. Re: Disable compression seems not to work
                        Alberto_aa Level 1

                        Thank you for remembering me to reset the preferences. Unfortunately no luck.

                        I've also tried updating to the latest version (that stayed exactly the same --> Adobe Photoshop Version: 2017.1.1 20170425.r.252 2017/04/25:23:00:00 CL 1113967  x64) but to no avail.

                         

                        I create the PSB (1.5GB) in this way:

                        - create a new blank 60.000x60.000 px image;

                        - duplicate the background 5 times;

                        - save.

                        • 9. Re: Disable compression seems not to work
                          Alberto_aa Level 1

                          Was finally able to have it to work.

                          Opened 5 5DSr raws as Layers and put 4 of them in hardlight and saved with compression disabled = 2GB (6 seconds).

                          Changed the setting to enable compression and resaved (not event needed to restart PS) = 1.3GB (82,4 seconds).

                           

                          Finally

                          • 10. Re: Disable compression seems not to work
                            davescm Adobe Community Professional

                            Hi

                            Well I was still puzzled so I saved with a plain white single layer file 1500x1000 pixels which uncompressed in 16 bit should take 9MB and in 8 bit 4.5MB as plain "Raw" RGB data. No matter how I set the "Disable file compression" in preferences the filesize on disk was a very compressed 94kB for the 8 bit and 170kB for the 16 bit - so some compression was obviously going on.

                             

                            I downloaded the PSD spec

                            Adobe Photoshop File Formats Specification

                            There are various parts of the file which can be compressed by different methods - the image data section is at the end.

                             

                            So I created some plain white single layer files of various pixel dimensions and opened them in Visual Studio with a binary editor reading them against that spec. This confirmed that apart from tiny pixel dimensions e.g. a 5x5 image , image compression does get applied to the image data regardless of the disable compression setting.

                             

                             

                            That preference setting is obviously impacting the level of compression in various parts of the file but it is not a simple "no compression" vs "some compression" switch.

                             

                            Dave

                            1 person found this helpful
                            • 11. Re: Disable compression seems not to work
                              Benjamin Root MVP & Adobe Community Professional

                              Wish Chris Cox still dropped in once in a while

                              • 12. Re: Disable compression seems not to work
                                Alberto_aa Level 1

                                Really interesting!

                                I'm pretty new to this stuff, I think I got the image data section start address but how can I understand if it is compressed or not?

                                In the example below there are 2 "uncompressed" PSB (in the sense that disable compression was checked):

                                - the left one is a 2x2 px 1 layer (background layer only) all white;

                                - the right one is a 10x10 px 1 layer (background layer only) all white.

                                • 13. Re: Disable compression seems not to work
                                  davescm Adobe Community Professional

                                  You can see the compression in two ways.

                                  The image data section immediately follows the byte with value 32 that you highlighted, and easy to work out on the 2x2 file.

                                  The first two bytes are 00 00 which , according to the spec. I linked previously, indicates Raw data i.e. no compression. This is confirmed in the following data which is 3 blocks of 4 bytes all set to FF. That corresponds to 4 pixels with R G and B all set to FF.

                                   

                                  If you then take a look at the second file you can see that those first bytes are now set to 00 01 which, according to the spec,  indicates RLE compression. The image data format is now very different and does not follow a straightforward R G and B value for every pixel. The section is also shorter than uncompressed which would take 300 bytes if in Raw format.

                                   

                                  Dave

                                  1 person found this helpful
                                  • 14. Re: Disable compression seems not to work
                                    davescm Adobe Community Professional

                                    Hi Benjamin,

                                    I get the impression that Chris Cox may not be  at Adobe now. If you look at his LinkedIn profile it states Senior Computer Scientist, Adobe Systems Incorporated Sep1996-June 2016. That is around the time we stopped seeing posts from him.

                                     

                                    I hope he is OK as his knowledge and insight was superb

                                     

                                    Dave

                                    • 15. Re: Disable compression seems not to work
                                      c.pfaffenbichler Level 9

                                      I get the impression that Chris Cox may not be  at Adobe now. If you look at his LinkedIn profile it states Senior Computer Scientist, Adobe Systems Incorporated Sep1996-June 2016. That is around the time we stopped seeing posts from him.

                                      Dang, that looks like bad news indeed. (Edit: Well, not exactly »news« in every sense of the word …)

                                      His knowledge was a valuable contribution to these Fora and while he may not have exactly »dumbed down« his replies as much as many a poster might have liked his patience and restraint seemed commendable to me.

                                      • 16. Re: Disable compression seems not to work
                                        davescm Adobe Community Professional

                                        Like I say - got to be careful, I've seen no confirmation that he has moved on, but that profile does seem to suggest that. Also his forum staff profile is shown as "Deactivated"

                                        I agree with you, Chris' posts were invaluable.

                                         

                                        Dave

                                        • 17. Re: Disable compression seems not to work
                                          c.pfaffenbichler Level 9

                                          I was impressed with how often he returned to try and explain issues (or Adobe’s stance on them) to people who apparently had problems processing the information he provided.

                                          And on the other Adobe Fora I occasionally visited (Illustrator and Indesign mainly) I got the impression that his involvement with users was not the norm among Adobe staff of a comparable position at other product teams.

                                          • 18. Re: Disable compression seems not to work
                                            Alberto_aa Level 1

                                            Thank you! Got it.