7 Replies Latest reply: Feb 22, 2008 5:12 AM by dave milbut RSS

    show jpeg-kompression

    McMaster05 Community Member
      Hi!
      Is it possible to see what kompression-settings were made when a jpeg was saved?
      When Saving you get that 0-100%-Slider. When I save an image with for ex. 60%, can I find out wheather it was 60% or 70% after saving?
        • 1. Re: show jpeg-kompression
          dave milbut Community Member
          >Is it possible to see what kompression-settings were made when a jpeg was saved?

          nope.

          >When Saving you get that 0-100%-Slider. When I save an image with for ex. 60%, can I find out wheather it was 60% or 70% after saving?

          what if the saving app didn't use 0-100% what if it used 1-10? or some other range (0-300)?

          bottom line. no, you can't tell. once it's saved it's saved. that data isn't retained anywhere.
          • 2. Re: show jpeg-kompression
            McMaster05 Community Member
            Ok, thanks, good to know...
            • 3. Re: show jpeg-kompression
              Bart Cross Community Member
              to add to wat dave said, the compression is relevant to the image.
              • 4. Re: show jpeg-kompression
                Nobody knows the 'settings', but one can draw
                some conclusions:
                1. the compression ratio Oldfilesize/Newfilesize
                for somewhat average photos:
                5..10 optimal quality
                20..30 average quality
                >40 rather bad quality
                2. accessible only for programmers: the content
                of the so-called quantization tables

                The program Quite a Box of Tricks by
                http://www.quite.com
                delivers quality/compression comments for JPEGs
                in PDFs.
                Such an information is very helpful for analyzing
                the compression state: resolution in ppi, kind of
                color space, kind of compression, for JPEGs: which
                quality.

                Best regards --Gernot Hoffmann
                • 5. Re: show jpeg-kompression
                  Рipkin Community Member
                  That's not bad: jpgQ - JPEG Quality Estimator (freeware) - http://www.mediachance.com/digicam/jpgq.htm
                  • 6. Re: show jpeg-kompression
                    McMaster05 Community Member
                    Cool, many thanks...
                    • 7. Re: show jpeg-kompression
                      dave milbut Community Member
                      from that site:

                      >Loss is adding up but not as many people think - if we use twice 75% first time then 75% second time it doesn't mean that the second round is equal to 55% of original quality (75% of first 75%). There is some loss but far less. So it doesn't work like your taxes.

                      as far as i know from what i've read, it does indeed give you 75% of quality EACH time you save. so with an assumption that flawed (assuming that i'm right, which is not always true <g>), how will his software "estimate" anything correctly?