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Can someone advise on JPEG compression

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  • Can someone advise on JPEG compression

    Hello all,

    all below pics were rejected due to JPEG compression
    1846093 Air Cairo Airbus A321-231 March 26, 2008 Rejected (Appeal) View Photo
    1846082 TNT Airways Boeing 747-4HAERF March 26, 2008 Rejected (Appeal) View Photo
    1846064 Martinair Holland Boeing 767-31A(ER) March 26, 2008 Rejected (Appeal) View Photo
    1846053 CSA Czech Airlines Boeing 737-55S March 26, 2008 Rejected (Appeal) View Photo
    1846045 El Al Israel Airlines Boeing 757-258 March 26, 2008 Rejected (Appeal) View Photo
    1846034 Air France (Brit Air) Fokker 100 March 26, 2008 Rejected (Appeal) View Photo
    1846029 Transavia Airlines Boeing 737-7K2 March 26, 2008 Rejected (Appeal) View Photo
    http://www.jetphotos.net/viewreject_b.php?id=1846029
    1846023 Transavia Airlines Boeing 737-7K2 March 26, 2008 Rejected (Appeal) View Photo
    http://www.jetphotos.net/viewreject_b.php?id=1846023
    1846014 Private Antonov An-2 March 26, 2008 Rejected (Appeal) View Photo
    http://www.jetphotos.net/viewreject_b.php?id=1846014

    Can someone please advise as I used the settings I always use.

    Thanks for your feedback,
    Joop

  • #2
    Joop, I'm afraid the rejections are correct, there is visible JPEG compression. But you've got so many great pictures in the DB. It must be something simple that you overlooked. Are you sure you used the same camera settings and workflow as usual?

    I think the best thing is to post an original together with the EXIF settings and have the forum decide what went wrong.

    Roel.

    Comment


    • #3
      Joop,

      All three have severe compression in the sky. With the first two, look at the aircraft and then move your eyes to the sky. Quickly move your head back 6 inches and then forward to where it was. The "blocky" compressed pixellation will become apparent as your eyes re-focus on the sky.

      The manipulation rejection for the AN2 is because of the monochrome conversion. It really doesn't work for this picture with the modern aircraft in the background. Not only that, it's also not the best monochrome conversion we ever saw. Blacks are not black and the greys are washed out. The compression is not so apparent as the monochrome tends to camouflage it but it's still there.

      Post an original and lets see if we can help.
      If it 'ain't broken........ Don't try to mend it !

      Comment


      • #4
        Hello all,

        I get crazy.. another one rejected on JPEG aretefact compression
        http://www.jetphotos.net/viewreject_b.php?id=1867087

        Here the original file:


        My last 10 pictures are rejected due to this reason while I haven't changed anything in my process.
        First i resize/save the file to the format of 1024 x 768. with options Baseline Baseline Optimized .Also the size. At the moment I'm using the 56.6Kbps.

        Then i close the original file and open the new file and continue processing there like sharpening, contrast, brightness or whatever needed.. When i think everythin is ok i upload the file.

        I,ve used this method for all my previous photo's as well so nothing new there.
        What is going wrong?
        Can someone please advise?

        Many thanks in advance,\
        Joop

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        • #5
          By any chance did all of your rejections for JPEG artifacts have an ISO160 setting?
          My contribution to JetPhotos

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          • #6
            Originally posted by Greg Wilson
            By any chance did all of your rejections for JPEG artifacts have an ISO160 setting?

            Could be but I'm not sure. But what would the iso have to do with that?

            Comment


            • #7
              Joop, the problem is your workflow. If you apply your workflow, in that way, the photos are edited twice that's one of the problems in your workflow. The other is to do the editing after resizing, that can cause the quality problem, too.

              So just start the editing workflow with contrast, levels, colors and so on, then resize your photos, and apply the sharpening at last and do the editing workflow at once, not with saving, opening and closeing the photos in the workflow. Just take Jid's workflow which is linked here in the forums as an example for your editing process, this will help you a lot.

              Comment


              • #8
                Joop, Peter is right in what he says. Do your cropping first then all your adjustments then resize and save.If you have to do any rework start off with the original.

                No artifacts

                Jid

                Comment


                • #9
                  Originally posted by Joop
                  Could be but I'm not sure. But what would the iso have to do with that?
                  The intermediate ISO speeds (certainly on the D30) are mathematical approximations, and not true sensor speeds.. These are done in the software which over/underexposed a little when shot, then boosted/dropped during the conversion, and don't really behave like the full-stop ISO modes do.
                  That is my understanding of a very technical problem. It may not be the answer to your problem, but it is as good a place to start.

                  Peter...working on a once saved file would not cause the problems Joop has in those photos
                  My contribution to JetPhotos

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                  • #10
                    Greg, working on jpeg file more than once causes compression problems, as the file is more compressed with every saving. The wrong workflow, reszing than applying such things as contrast, levels, etc. gives the photo the rest.

                    Wrong ISO settings will mainly cause noise/grain, but not compression artefacts.

                    Comment


                    • #11
                      Peter...I say again......saving once ...or even a couple of times and reworking a file will not give the problems Joop has.....look at the top of the trees...it is major.
                      And I am not talking about ISO and noise....I am discussing the use of intermediate ISO settings ISO160 etc...the setting on his latest reject......and the way 1/3 and 1/2 stop ISO is achieved.
                      With all due respect I am trying to get Joop to look at his other variables.......it may not be his problem....but don't dismiss it is a thought...... but sheesh it is the same old tired story .....dare not think otherwise than it has to be Canon..it has to be IS, it has to be PS3 ....and then you will be a good photographer.
                      My contribution to JetPhotos

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                      • #12
                        Gerg maybe those variables maybe worth a thougt, but this problem isn't caused by them.

                        It's a simple problem caused by the editing process, and it's not depending on one specific editing software, it'll be caused by any. Just compare the rejected one to the one Jid has posted earlier in this thread before, you can clearly see the difference. And you can believe me, the multiple saving is the main problem here, as you get more compression to the photo with every time saving it, because of jpeg is a compressed file format.

                        Comment


                        • #13
                          Hello all,

                          Firstly thanks a lot for your constructive feedback.
                          Reading all the comments i came to the conclusion that's actually what i used to do:
                          1. opening the file.
                          2. check if there are dust spots
                          3. check/adjust contrast, colors etc.
                          4. resize to 1024 x 768
                          5. save (baseline standard, quality maximum, baseline standard)
                          6. open resized file and sharpen.
                          7. save again
                          8. upload.

                          Recently i was hit by a virus causiing me literally a hell of a headache.
                          Probably the headache caused a shortcircut which made me do step 3 after step 5 ..

                          I'll start with fresh optimism and have good hope the next batch of uploaded photos will cause less frustration.

                          Cheers,
                          Joop

                          Comment


                          • #14
                            Joop, do not save the file and reopen it for sharpening and save it again, this would/can cause compression, too. Just do the complete editing process at once. If you need to save it during the editing process, do not use the jpeg file format, use a non compressed file format, just as tiff, this won't bring compression artefacts to your photos but the file size will get a lot larger.

                            Comment


                            • #15
                              Originally posted by degi
                              Joop, do not save the file and reopen it for sharpening and save it again, this would/can cause compression, too. Just do the complete editing process at once. If you need to save it during the editing process, do not use the jpeg file format, use a non compressed file format, just as tiff, this won't bring compression artefacts to your photos but the file size will get a lot larger.
                              You're totally right,
                              First of all i will do all editing as specific workflows, resize and save only one.
                              Once you re-open it and let's say sharpening or whatever and save again. That process can cause Jpeg Compression

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