Skip navigation
Currently Being Moderated

jpeg File Save & Loss Rate in PSE

Jul 19, 2013 9:42 AM

When working on jpeg files in the PSE Editor, does PSE perform an automatic internal file "Save" after each adjustment, (i.e., levels, color, etc.)?  I have always assumed that the file does not get saved until the user performs a manual save after all editing has been completed.

 

If automatic internal "saves" are performed after each adjustment on a jpeg file. then image degradation could be accelerated beyond what one would expect, i.e., each Save of a jpeg file reduces image quality.  If these automatic Saves are being performed, then I guess the only way to edit files is in a psd format, then save the final psd file to a jpeg format to conserve disk space.

 
Replies
  • Currently Being Moderated
    Jul 19, 2013 10:08 AM   in reply to Bob Ward

    Bob Ward wrote:

     

    When working on jpeg files in the PSE Editor, does PSE perform an automatic internal file "Save" after each adjustment, (i.e., levels, color, etc.)?  I have always assumed that the file does not get saved until the user performs a manual save after all editing has been completed.

     

     

     

    Yes.  All the save takes place when the user presses the save button.  Therefore, if you are working on a file and you have  power failure, you are likely to lose all your changes unless, of course, you saved your work at a specific time on your project.

     

    There are pros and cons of saving the file at certain interval but this is not the place for this discussion now.

     

    You've made a very good point though.

     
    |
    Mark as:
  • Currently Being Moderated
    Jul 19, 2013 11:35 AM   in reply to Bob Ward

    Bob Ward wrote:

     

    When working on jpeg files in the PSE Editor, does PSE perform an automatic internal file "Save" after each adjustment, (i.e., levels, color, etc.)?  I have always assumed that the file does not get saved until the user performs a manual save after all editing has been completed.

    Yes.

     

    If automatic internal "saves" are performed after each adjustment on a jpeg file. then image degradation could be accelerated beyond what one would expect, i.e., each Save of a jpeg file reduces image quality.  If these automatic Saves are being performed, then I guess the only way to edit files is in a psd format, then save the final psd file to a jpeg format to conserve disk space.

    No, the 'in memory' format is not saved to the drive unless you manually choose to 'save as'.

    If you periodically save a jpeg version (overwriting the older ones), without closing the file,  jpeg compression changes are not cumulative. The 'in memory' version is kept unchanged. It's not like you save to jpeg, close and re-open, in which case the jpeg double compression would have taken place.

    If you want periodic saves in a long editing session of a picture, it's best to save as psd, because that saves layers, selections... It's also better if you work in 16 bits. If you save in jpeg, the jpeg compression will be done only once, there will be no cumulative loss of quality.

     
    |
    Mark as:
  • Currently Being Moderated
    Jul 19, 2013 11:25 PM   in reply to Bob Ward

    The misunderstanding seems to be that when you are working on a file without closing it, you are still working on the 'in memory' format (you can think of it as psd format). If you hit 'Save as' or 'Save' in jpeg format, the compression takes place and while you are still working with the uncompressed 'in memory' data, the file saved on the drive is compressed. If you save ten times in you working session, overwriting the former save, there is only one compression. Of course, if you close the file and re-open it, you are starting from a compressed file and it is compressed a second time when you save it again.

     

    The loss of quality when saving as jpeg was a more serious concern years ago, with low pixel count pictures and the urge to save space. Today, it's not really a problem if you are using low jpeg compression levels with high megapixel pictures : just test it by yourself and see if saving the same jpeg ten times, closing and reopening leads to a visible loss.

     

    More seriously, it is advisable to store all intermediate editing saves as psd or tiff, even if you only keep the final jpeg. And today, the real way not to lose any quality is to shoot raw...

     
    |
    Mark as:

More Like This

  • Retrieving data ...

Bookmarked By (0)

Answers + Points = Status

  • 10 points awarded for Correct Answers
  • 5 points awarded for Helpful Answers
  • 10,000+ points
  • 1,001-10,000 points
  • 501-1,000 points
  • 5-500 points