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  • JPG Compression Artefacts

    https://www.jetphotos.com/viewqueued_b.php?id=5871626 rejected for JPG Compression Artefacts.
    What are they and how do I fix.
    Shoot in RAW, process in Camera Raw and Photoshop / Export / Save for Web (Legacy)
    Thanks for the help.
    Malcolm

  • #2
    Malcolm,
    I had the same problem for a long time, but by changing the saving process I rarely get pictures rejected for JPG compression artefacts.

    After I have processed the picture I resize it and then save it in high quality as JPEG/JPG from Photoshop so only one program is used. As I understood the compression artefacts can happen if you use more than one program (for me it was Irfanview to resize and sharpen).
    Best regards

    Peter Lund

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    • #3
      When saving for web, make sure to save at 100% quality by using the slider. Your rejected image seems to have been saved at a lower quality after editing. Compression artefacts can be seen all around the aircraft, it looks like small grain pixels. For example, look closely at the tail, around the edges of any details there are small grainy compression artefacts.

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      • #4
        Click image for larger version

Name:	170511_FRONTIER_N229FR_PHX_R100_DSC7686.jpg
Views:	1
Size:	708.0 KB
ID:	1015838 Thank you both very much. Apparently Quality was a default 60. Attached saved at 100. What do you think? Thanks. Malcolm

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        • #5
          Yip, that's better, no compression visible now. Just watch out that the quality slider remains at 100%, sometimes it can revert back to the original setting which in your case is 60%.

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          • #6
            Great. Thank you all very much!
            Malcolm

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            • #7
              Dave Henderson DC-3

              Also, Mr. Chips. Really like your DC-3 pictures. Grew up in the Caribbean in the 1960's when they were THE local airliner. Wish I'd taken more then, making up for it now.
              Malcolm

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              • #8
                Just to point it out again in one go: the best way to avoid JPG compression artefacts is ...
                - if shooting JPG, set the camera to highest quality - lowest compression
                - save only once, as the very last step (as mentioned by Peter Lund above, thx)
                - use only minimal noise reduction, if any
                - save at the highest quality - lowest compression settings

                that should do it.
                My photos on Flickr www.flickr.com/photos/geridominguez

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                • #9
                  Originally posted by MTPatx View Post
                  Also, Mr. Chips. Really like your DC-3 pictures. Grew up in the Caribbean in the 1960's when they were THE local airliner. Wish I'd taken more then, making up for it now.
                  Malcolm
                  Thanks Malcolm, always happy to see a DC-3 these days, doesn't happen very often but when it does, I treasure the moment!

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                  • #10
                    Hi!

                    Can you give me a hint, where do you spot compression artefacts in this pic:
                    https://www.jetphotos.com/viewqueued_b.php?id=5875318

                    Best regards
                    Daniel
                    Best regards
                    Daniel K.

                    ----------

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                    • #11
                      Originally posted by dakl View Post
                      Hi!

                      Can you give me a hint, where do you spot compression artefacts in this pic:
                      https://www.jetphotos.com/viewqueued_b.php?id=5875318

                      Best regards
                      Daniel
                      Sorry for the late reply, nothing there that I would consider compression however it is indeed a bit soft.

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                      • #12
                        Originally posted by Mr Chips View Post
                        Yip, that's better, no compression visible now. Just watch out that the quality slider remains at 100%, sometimes it can revert back to the original setting which in your case is 60%.
                        Shot was originally rejected due only to JPEG Artefacts. Resubmitted with Quality set to 100% as suggested. Just curious how that could result in Over Exposure and Back Lit rejections on the resubmittal.

                        https://www.jetphotos.com/viewqueued_b.php?id=5896700

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                        • #13
                          Originally posted by MTPatx View Post
                          Shot was originally rejected due only to JPEG Artefacts. Resubmitted with Quality set to 100% as suggested. Just curious how that could result in Over Exposure and Back Lit rejections on the resubmittal.

                          https://www.jetphotos.com/viewqueued_b.php?id=5896700
                          Overexposed I can see, but doesn't appear to be backlit to me.

                          Each image is re-screened after it is re-submitted, likely by a different set of eyes. Even if you've only changed one thing, we don't know this so need to start the screening process from the beginning. This may result in things that were missed on the first screening being caught the second time through.

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