What compression should I use?

[raycer]

Hi
I have been scanning my old negatives in Canon Canoscan 8800F and editing them in Photoshop Elements 5.
After this I saved them with Photoshop Elements 5 with the Image Options in the JPEG Options dialog set to 12 Maximum.
However, I have read that saving at this setting increases the file size and that the setting should be 10 - still on Maximum. I have tried this and it cuts the file size by approximately two thirds and I can't see any degradation in zooming in on the image. Is there any reason for not saving at this amount of compression?
Hope someone can advise me
Regards

[dj_paige]

JPG quality levels are related to compression amounts. The smaller the quality number, the smaller the file, but also the lower the quality.

For most images, the human eye cannot see the difference between different quality levels one or two numbers apart (for example, 10 vs 12) unless you blow up the image very large and you know exactly what to look for. Thus, unless you are planning to print the image at or near its maximum printable size (or view it regularly at nearly 100%), 10 is better than 12 because it is smaller, and you can't see a difference.

I save many .jpgs at 8 simply because I have never printer at greater than 8x10, and probably 95% of my prints are done at 4x6;

[TonyW]

Actually I've even read somewhere that there's even a downside to saving at low compressions - especially with scanned images. You start to save all the tiny artifacts in the scanned negative. I rarely save anything above 8. You can get an idea of the impact by using Save for Web - the scale is different (0-100 instead of 1-12) but above about 50 (which I assume is about 6) you'd be hard pressed to see any difference even if you zoom right in and examine every microscopic detail.

Tony

[raycer]

Thanks for your tips Paige and Tony.
I'm certainly going to save a helluva lot of space on my hard drive and back up with the lower setting you recommended.
It's just galling to think that since I got my scanner a year ago I've saved over a thousand of my old photos at this large file size.
Thanks again.
Regards Raycer