If you open, edit, and save a JPEG, it loses a little quality each time.
- Every time you use the "save as" function, the JPEG quality degrades slightly.
- You may save a jpeg many times w/in a single editing session without loss.
- For editing, work in TIFF, BMP, or PNG format.
- For long-term hard-drive storage, keep a TIFF, BMP, or PNG copy.
- You may copy/paste the file icon to duplicate a JPEG file without loss.
Improving Resolution and Enlarging Image (PhotoShop):
First change resolution, then enlarge. Uncheck 'resample' and change resolution (suggested: 300 res). Save and close. Re-open file and change size. You can enlarge up to a point, but watch for degradation of image. Zoom in and look everything over. Print a copy to test it.
----
To determine high-resolution PRINT SIZE:
Take the required print dimension in inches and multiply by 300 to get the necessary pixel dimension.
Example to find necessary pixel width:
If 10" x 8" print size is needed: 10" x 300 = 3000px width needed.
- If 5" x 7" print size is needed: 5" x 300 = 1500px width needed.
- An image file with a pixel width of 400px will produce a tiny print of about 1.3 inches.
- An image file with a pixel width of 2100px will produce a 7" wide print.
- 3000px divided by 300 = 10" wide print (at high res).