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JPEG saving issues
Icebear
Registered Users Posts: 4,015 Major grins
There have been a number of threads here with dealing with the issue of shooting/processing/saving JPEG format. The ready answer seems to be "shoot RAW" which is clearly the best answer, but lots of folks on this forum don't have that option.
I ran across this information this morning in Photoshop CS3 Bible, by Fuller and Fuller (pg 144). Those of you limited to JPEG might find it useful. The italics are the authors - the bolding is mine, and is the idea I found potentially useful to those having a hard time grappling with this issue.
"JPEG is a cumulative compression scheme, meaning that Photoshop recompresses an image every time you save it in the JPEG format. There's no disadvantage to saving an image to disc repeatedly during a single session, because JPEG always works from the onscreen version. But if you close an image, reopen it, and save it in the JPEG format, you inflict a small amount of damage."
Hope this helps you.
I ran across this information this morning in Photoshop CS3 Bible, by Fuller and Fuller (pg 144). Those of you limited to JPEG might find it useful. The italics are the authors - the bolding is mine, and is the idea I found potentially useful to those having a hard time grappling with this issue.
"JPEG is a cumulative compression scheme, meaning that Photoshop recompresses an image every time you save it in the JPEG format. There's no disadvantage to saving an image to disc repeatedly during a single session, because JPEG always works from the onscreen version. But if you close an image, reopen it, and save it in the JPEG format, you inflict a small amount of damage."
Hope this helps you.
John :
Natural selection is responsible for every living thing that exists.
D3s, D500, D5300, and way more glass than the wife knows about.
Natural selection is responsible for every living thing that exists.
D3s, D500, D5300, and way more glass than the wife knows about.
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The damage comes with saving the open image to a file on a hard drive, when the jpg compression is applied whether by Photoshop or your camera's in camera software to the saved file itself.
When the saved image is re-opened it is no longer an exact duplicate of the image that was previously seen on screen prior to saving.
Now if you save a jpg at quality level 10, and then re-open it, you will not "see" any difference to the human eye, but the numbers that comprise the image will have changed slightly. If you now save this image a second time, further changes will be applied. This is why cumulative damage occurs to an image with repeated opening and saving during an editing workflow.
If you shoot jpgs, rather than RAW, just archive your original jpgs, and only edit copies of them. If you never re-save on top of your original archived jpgs, they will be exactly as they came out of the camera on your memory card.
Moderator of the Technique Forum and Finishing School on Dgrin
If I'm processing .jpg file, I'll save it as a .psd file or an uncompressed .tif file. I always flag the original .jpg file as read-only as soon as they're downloaded from the SD card.
With the .psd file or uncompressed .tif I can then do my processing, save it, come back later and resume my workflow without having to be concerned with compression issues. To me this is especially important when cropping at a later time so I don't end up making a compressed .jpg crop of a compressed .jpg file.
The downside to this is larger file sizes eating up more HD space.
http://cafields.com
:jawdrop
I'm sure many of you out there have worked with larger, but it caught me by surprise.
Natural selection is responsible for every living thing that exists.
D3s, D500, D5300, and way more glass than the wife knows about.
I partitioned that drive, as two 250 Bg drives - one to back up my main computer hard drive with operating system and applications, and the other to be a secondary backup of my data ( image ) files. I also have my data files on a third hard drive and many of my better images on DVDs as well.
Moderator of the Technique Forum and Finishing School on Dgrin
Personally, when I make any changes to a .jpg file, I make a new file simply calling it eg: file001abcM1.jpg or xxxxxM2.jpg
Doing this always saves the file in its ori volume. "Save As" is key here. Unless I am missing something in the question, this works flawlessly.
Not sure if this is what you were looking for but it works other than to make a sub-directory (as I do) called "worktable" and then doing a .tiff conversion from .jpg to .tiff via Faststone bulk conversions. Once a .tiff file, you can do anything to the file you want without hurting it.
Yes... No ... ??
...Steve
I'm Canadian, eh.
The days of emailing images is quickly coming to an end.