Degradation of JPEG Pictures with repeated viewing

  griffon 56 23:21 07 Oct 2004

As I understand it JPEG photos degrade with repeated opening and closing. Has anybody got info on how many repetitions are possible before there is a noticeable degradation? Secondly, does such degradation mean that it's necessary to backup your photos as soon as you load them from your camera, or print them out before you screen them too often?

If there is degradation and no way of stopping it, digital photography is beginning not to look the wonder of the age. Comment?

  Robespiere 23:42 07 Oct 2004

all jpegs, even at 100% will degrade as this is a lossy file type

  marjted 23:42 07 Oct 2004

If you save in a non-lossy format such as TIFF, there is no degradaton of the image but the files are larger. Repeated saving in JPEG, even at top level compression still results in a loss of quality, although it would take a fair number - have seen 20 times quoted- before the loss was evident to the naked eye.

  TomJerry 00:20 08 Oct 2004

Nothing changed to the file, no matter how many times you open and close a jpeg file use a jpeg viewer.

If you do not believe, check file size and date before you open and close, then open and close to see any difference.

ONLY situation you loss information is when you open and "SAVE" it again with the same file name. If you do any editing, you will need to save hence some degradations of quality.

You only need to backup if you intend to change anything using any photo editing package.

  The Spires 00:41 08 Oct 2004

You live and learn.

  powerless 00:45 08 Oct 2004

MD5 check it people.

  griffon 56 23:47 11 Oct 2004

Thanks everybody,

However, there seems to have been just a little confusion. I asked if there was degradation to a jpeg photo caused by repeated opening and closing, not to edit it in any way or to 'SAVE' it by a menu command. I use Adobe Photo de Luxe Business Edition for viewing and editing running in Win 98SE. I thought that I had detected a loss of sharpness in a couple of photos after looking at them on several different occasions.

I take it that if there was degradation it was not due to just opening, looking and closing the photo. Thanks again.

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