24 Replies Latest reply: Jul 8, 2010 4:28 PM by Phillip Jones RSS

    Acrobat not optimized for .png ?

    Christian Davideck Community Member

      Hi everyone.

       

      I need to convert a 750 kb png file (8bit RGB, no transparency) into a .pdf file, which I have to keep as small as possible.

      So I open the .png file in Acrobat and save it as a .pdf

      I would have expected a resulting ~770-800 kb .pdf,

      however it turned out to be an unsatisfactory 1164 kb.

       

      While I do understand that encapsulating a .png file into a .pdf file will inevitably and inherently increase the file size, but the container alone needs about ~20 kb. So there is something else going on here.

       

      From my observations, I get the impression, that the .png file's binary content is not embedded 1:1 into the .pdf file, but interpreted - meaning that the .png content is decoded into a full resolution bitmap image ... which is then recompressed according to the settings in edit > preferences > categories > convert to pdf > png > edit settings > compression > color

       

      I want the conversion to be lossless, so the only possible options here are "ZIP" and "JPEG2000 (quality:lossless)". But both options invariably lead to the same file size mentioned above (~1164 kb).

       

      So my question is:

      Is there ANY way to convert a .png file into a .pdf file by simply embedding the .png content, i.e. without decoding the .png into a bitmap image and recompressing it?

       

      Many thanks!

       

      PS: I am on Acrobat Pro 8, and familiar with all the options in PDF optimizer (which were not capable of substantially reducing the .pdf file size without resorting to lossy image compression)

       


      PPS: I can upload a sample file if need be.
        • 1. Re: Acrobat not optimized for .png ?
          Christian Davideck Community Member

          Okay, sure enough further tests seem to confirm my apprehensions. I created a 3500x2500 gradient in Photoshop which compresses to a 129 kb .png file, but Acrobat produces a 14 times larger .pdf file with 1838 kb from that same .png ;(

           

          (So my question still stands if anybody can help me.)

          • 2. Re: Acrobat not optimized for .png ?
            Phillip Jones Community Member

            Go to Pdf Optimizer and when window opens, select image Click her for illustration.

            Next set to what compatibiliy you want I'd say for Acrobat 5 is about right. PC people are natorious for not updating progans until they don't work. about 90% of the world is still using Acrobat 5.

            If your sure they use the latest version set for acrobat 9 which gives the greatest  compression of the files.

            Next  in image widow and set for no more than 150 DPI for first two items Unless this is to be turned in to be printed. the last item leave a 300dpi. Naturall if its to be printed ina report, book or Magazine no less than 300dpi.

             

            Then go to last item and set these items in this illustration if you don't intend for post on web don't check, or uncheck the last item at bottom of page.

             

            Note: when you click on links you'll have to click on back button in your browser to get back to this thread

            • 3. Re: Acrobat not optimized for .png ?
              Christian Davideck Community Member

              Phillip, I thank you and honestly appreciate your help.

               

               

              But I went out of my way to provide fairly detailed information about the problem, my objective and what I've already tried so far and you hardly take any of that into account, ignoring specifically that I said I'm "familiar with all the options in PDF optimizer (which were not capable of substantially reducing the .pdf file size without resorting to lossy image compression)". I have already maxed out ALL non-image settings for maximum compressibility. As for the image compression, my OP stresses twice that it needs to be lossless, thus not allowing for the DPI reduction you suggested (which besides is in many cases – including mine – a not so good idea because well compressible PNGs, such as non-photographic imagery, may even end up increasing in file size due to the anti-aliasing involved in the DPI reduction).

               

               

              My objective and my question highlighted above in yellow still stand. Is there no way to preserve the PNG's bitstream when converting to .pdf? Do I really have to settle for a 200%-1400% increase in file size (as shown by the examples above)?? And more generally speaking: Is Acrobat 8 incapable of using PNG compression for images? If no, how is this possible, given that PNGs have been supported by all major Internet Browsers for more than a decade!

               

               

              Thank you.

               

               

              PS: Here is the 129kb .png file from posting #2 in case anyone wants to try a .pdf conversion

               


              gradient.png

              • 4. Re: Acrobat not optimized for .png ?
                Phillip Jones Community Member

                Sorry, I wasn't much help I downloaded the pnf and I show as somthing 20 by 30 inches wide and when Open it in GRaphic Converter shows its a 32bit image. If the png was created on a PC then TRanfered to PC it will always big bugger. Someone smarter than I will have to explain why. Even If I rudece it down to 8.5 by 11 and I still save as a PDF I get a resultant file of 1.5 mb.

                 

                There might be a  way to save a .ps File then open in Acrobat or distiller and get a smaller file.

                • 5. Re: Acrobat not optimized for .png ?
                  Christian Davideck Community Member

                  I still thank you very much for your efforts, that's kind.

                  And no, png is an OS-independent format.

                  • 6. Re: Acrobat not optimized for .png ?
                    Phillip Jones Community Member

                    Have you tried the possibily of saving as a .ps file then opening in acrobat?  I am aware that PNG works across all OS types. But I've heard (I can't vouche for myself), that image files that brought across from PC to Mac have a tendency to become larger for some reason (this may not apply to your situation). You might open in PHotoshop and save as a PDF from there.

                    • 7. Re: Acrobat not optimized for .png ?
                      Christian Davideck Community Member

                      None of the above preserves/embeds the png bitstream 1:1 in the pdf file, thus unnecessarily increasing the file size.

                       

                       

                      I think pdf is not capable of handling png files, which is a shame given that they have been around for more than 10 years, are supported by >99% of current web browsers and are the only wide-spread and powerful lossless compression for image files.

                       

                       

                       

                       

                      • 8. Re: Acrobat not optimized for .png ?
                        urinal-fS6nU9 Community Member

                        I also looked into this for a few days trying to find an optimal solution. Both png and jpeg 2000 result in a "lossless tax" which makes me very sad. PDFs seem optimized for jpegs. I guess for those of us who care about file size, we have to look elsewhere. This makes me sick :-(

                        • 9. Re: Acrobat not optimized for .png ?
                          Christian Davideck Community Member

                          urinal wrote:

                           

                          This makes me sick :-(

                          true.

                          unbelievably sad and idiotic state of affairs ...

                          • 10. Re: Acrobat not optimized for .png ?
                            MichaelKazlow CommunityMVP

                            The issue may have been solved in Acrobat 10, but maybe not. I'd recommend posting to:

                             

                            https://www.adobe.com/cfusion/mmform/index.cfm?name=wishform

                             

                            Perhaps better support for png can make it into Acrobat 11, now that pdf is a standards based file format changes to how it supports different file formats may take time.

                            • 11. Re: Acrobat not optimized for .png ?
                              Phillip Jones Community Member

                              You realize that we have been using Acrobat 9 roughly 2 years plus. based on when we had last Major upgrade we are talking about possible 2-6 year wait for Version 11.

                               

                              I've been reading about the PNG format and specs for it was adopted back as far as as 1995 latest Spec were put out in 1998.  You think a File format that's been out for 12-15 years Adobe would have gotten a handle on by now. It was created as an open Source replacement for Gif format, as the creators of GIF slapped on an exorbitant licensing fee for use.  Its actually a Lossless replacement for GIF.

                              • 12. Re: Acrobat not optimized for .png ?
                                Christian Davideck Community Member

                                PjonesCET wrote:

                                 

                                I've been reading about the PNG format and specs for it was adopted back as far as as 1995 latest Spec were put out in 1998.  You think a File format that's been out for 12-15 years Adobe would have gotten a handle on by now.

                                 

                                Absolutely correct, Phillip Jones. You hit the nail on the head.

                                It's all the more incomprehensible as in its Creative Suite, Adobe bundles Acrobat with other products supporting png (such as Photoshp). So Adobe clearly knows how a png file is designed (Photoshop reads AND writes png files). Why they decide NOT to use this knowledge is beyond me.

                                 

                                 

                                MichaelKazlow wrote:

                                 

                                The issue may have been solved in Acrobat 10, but maybe not.

                                 

                                 

                                I don't have Acrobat 10. Can anyone please confirm/refute ?

                                • 13. Re: Acrobat not optimized for .png ?
                                  Phillip Jones Community Member

                                  Acrobat 10 misn't even out yet, and no time table as to when it will be ready

                                  • 14. Re: Acrobat not optimized for .png ?
                                    Christian Davideck Community Member

                                    okay, what about Acrobat 9? Can anyone check?

                                    • 15. Re: Acrobat not optimized for .png ?
                                      Phillip Jones Community Member

                                      Acrobat Doesn't create anything unless you create from scratch. it takes anything imported into  through distaller which or  the PDFPrint driver OSX.5 and lower or through the create adobe quality PDF from the Mac Print Menu >PDF>create adobe quality PDF. Once created, and works with it Minor Editing can be done and you can remove and replace images. And even with various tools including PDF Optimizer you can compress the files.

                                       

                                      If you have access to the original Graphics from a website.  you might be well served to redown load them directly then replace  them with the ones you've downloaded see if that has an effect.

                                      • 16. Re: Acrobat not optimized for .png ?
                                        Christian Davideck Community Member

                                        Phillip, thank you for your reply, but you are unnecessarily complicating the issue and the points you mentioned are irrelevant to the issue at hand.

                                         

                                         

                                        This thread is only about one thing:
                                        converting a .png file to a .pdf file

                                         

                                         

                                         

                                        Maybe someone could take the .png file posted above (rainbow gradients) and convert it to .pdf with Acrobat 9 (just drag a .png file into an empty Acrobat window and save it there) and check the resulting file size (to see whether the pdf uses png compression) ?

                                        • 17. Re: Acrobat not optimized for .png ?
                                          Phillip Jones Community Member

                                          Okay I've taken your png image and use Craphic Converter  to convert it to PDF

                                           

                                          http://screencast.com/t/ODBjOTUxM I did a getinfo on the file  and the screen shoot is the result.

                                           

                                          You can  download the file for yourself : http://www.phillipmjones.net/gradient.pdf

                                           

                                          You can see what the size is for yourself your welcome to download it yourself.

                                           

                                          I used an image editor Graphic Converter to convert your image from png to pdf.

                                           

                                          You could just as easily use FireWorks, or for that matter PhotoShop or any other image editing Program

                                          • 18. Re: Acrobat not optimized for .png ?
                                            Christian Davideck Community Member

                                            Okay, many thanks for helping Phillip, but you didn't convert the png file I posted, only its preview image.

                                            You get the full-size image by clicking on the preview image above.

                                            The exact location is: http://forums.adobe.com/servlet/JiveServlet/showImage/2-2832523-28566/gradient.png

                                             

                                             

                                            (I don't have FireWorks, but mentioning Photoshop is a moot point because Photoshop does not preserve an image file's bitstream, but decompresses it for editing purposes. I have PS CS3 and if choose to save to pdf, the following compression methods are available: zip, jpeg, jpeg2000. NOT png)

                                            • 19. Re: Acrobat not optimized for .png ?
                                              Phillip Jones Community Member

                                              Check this out:

                                               

                                              http://screencast.com/t/Y2FjY2RiYT

                                               

                                              Now use: same home page as before for actual file: except use this for the actual file name

                                              gradient_2_.pdf

                                               

                                              As you can see in Optimizer  in acrobat : http://screencast.com/t/NmI4Yzg5

                                               

                                              will only handle Jpeg. if you click on jpeg button in optimizer there are three choices, Original, jpeg and none)

                                               

                                              I've uploaded  two additional file changing version to acrobat 9 format, and chage compression to Original.

                                              gradient_2_3.pdf

                                              gradient_2_.4pdf

                                               

                                              Regardless of what you do the file size will be about what I have in these examples or even larger.

                                               

                                              I'll see if I can use Acrobat to insert an image in a Blank PDF and see what happens

                                               

                                              Just Tried: You can't insert a Png image in a PDF from Acrobat you can a jpeg but not a PNG.


                                              Sorry this I all the help I can be.

                                               

                                              Message was edited by: Phillip Jones new item

                                              • 21. Re: Acrobat not optimized for .png ?
                                                Christian Davideck Community Member

                                                thank you for your test.

                                                So you used Acrobat 9, right?

                                                This confirms that Acrobat 9 still doesn't preserve PNG's but transcodes

                                                them to something else and thereby either decreasing quality or

                                                increasing file size, often both ...

                                                Sad, sad, sad for a software priced at 600EUR ...

                                                Adobe, fail ...

                                                • 22. Re: Acrobat not optimized for .png ?
                                                  Phillip Jones Community Member

                                                  Acrobat should support any Graphic Fille Format out their Particularly since other products adobe has does. Photoshop comes to mind, possibly InDesign. DreamWeaver. But not Acrobat.

                                                   

                                                  contact this : https://www.adobe.com/cfusion/mmform/index.cfm?name=wishform and voice your concerns.

                                                   

                                                  Also, pose this question why PNG is not supported in Acrobat in The Adobe.Feedback Forum

                                                  • 23. Re: Acrobat not optimized for .png ?
                                                    Christian Davideck Community Member

                                                    I agree with you, Phillip.

                                                     

                                                    Well I wouldn't go as far as demanding support for any image file

                                                    format, but at least the most popular and wide-spread ones. And what are

                                                    the most popular formats? Without any doubt the most wide-spread lossy

                                                    image compression format is JPEG and the most wide-spread lossless image

                                                    compression format is PNG. One would expect at LEAST those 2 to be

                                                    implemented! It's a shame, as I said, for a 600EUR program to be

                                                    incapable of something most freeware programs can do ...

                                                     

                                                    Okay, maybe I will use the wishform, but I don't have much hope for

                                                    this. It's not as if guys @ Adobe don't know what PNG is. They may have

                                                    their reasons marketing wise to deliberately prevent PNG from being

                                                    implemented as a compression scheme.

                                                     

                                                    What is the Adobe feedback forum? Is it this here:

                                                    http://forums.adobe.com/community/general/adobedotcom_feedback

                                                    ?

                                                    But this seems to be a forum for feedback on the adobe.com website only.

                                                    • 24. Re: Acrobat not optimized for .png ?
                                                      Phillip Jones Community Member

                                                      There are two shown side by side in list. The forum Comments is the one for comments on the forums.

                                                      The other the one I suggested is suspposed to be for comments similar to wishlist.

                                                       

                                                      There have been plenty of people that uses Adobe.feedback to exprees concern for Adobe products.

                                                       

                                                      If you get told otherwise you've already posted so what difference does it Make. Couldn't hurt.