JPEG Files

[Canonshooter]

Hi all. I was wondering, if a picture is taken in jpeg format, edited, and then saved as a copy of the original jpeg, will this degrade the image quality of the original image? And will the image quality of the copy be low quality? And one last question. If I keep saving copies of the original image, will the quality decline in the original image?

Thanks all so much

[Scottes]

Every time you save as JPEG it degrades the image. It might not be noticable, but it is there. If you plan on doing a lot of edits and saves you're better off converting to a loss-less format (TIFF, PSD) and then save that as JPEG. Never open a JPEG, edit it, and save it. Always open the TIFF and Save As.

Again, the quality loss might not be noticable, but it does happen.

[PeterS45]

As long as you keep the original and save your copy as a new file the original won't be changed and therefore will keep it's quality.

[John_T]

Better yet, shoot RAW (CRW) and convert to 8bit tiff and work with the tiff. If you goof up the tiff, you can always go back to the original CRW, make a new tiff and start over.

[jfike]

It's also possible to save a file in jpeg format at 100% quality (at least PhotoImpact gives you that option). I usually default to that setting (100%) until the final edit is finished. Also, as Peter45 stated, keep an original copy.

[atleypnorth]

100% quality doesnt mean that there is no data loss. Going above 95% is pretty pointless since data loss doesnt decrease above that level

[PacAce]

Hi all. I was wondering, if a picture is taken in jpeg format, edited, and then saved as a copy of the original jpeg, will this degrade the image quality of the original image?

No, not of the original image. However, the image of the copied image will be degraded.
And will the image quality of the copy be low quality?
Depends on how much compression you used but it WILL be lowER quality than the original.
And one last question. If I keep saving copies of the original image, will the quality decline in the original image?

No, if you save the copies using a different filename from the original, but Yes if you save it as the original filename.

[John_T]

Jpeg may also degrade on rotation and other manipulations, get pixel and color shifts.

Jpeg is for cross-platform sharing, internet and P&S to print.

If you are into photography, post processing and imaging, you will use jpeg for the web and e-mail, but you will shoot in RAW and process in tiff and/or psd. There is no way around it.