PS/PSE JPEG Quality Settings: 9, 10, 11 or 12

[SteveLig]

Zenfolio suggests using a lower Quality setting (10) when saving JPEG files for upload because there really isn't much of a drop in quality between the 10-12 settings but at 10 the file size is significantly lower.

I tried this earlier today using the same images re-saved at quality settings 9, 10, 11 and 12. Much to my surprise, this seems to be true. Here are the numbers from one of the tests:

4,149 KB - original
4,675 KB - 12
2,451 KB - 11
1,548 KB - 10
1,117 KB - 9

I would have expected to see at least some difference between the images but at 100% viewing I could see none between the image qualities 10-12. And to be honest, I really had to strain to see a difference in the one saved at IQ 9. (I was using PSE5 for the tests.)

Has this been other's experience? I'm not sure how you can cut the file data by half and not be able to detect a visual difference. Am I missing something here? Does it depend on the scene and what is being captured? Am I thinking about this correctly?

Thanks for any thoughts!

Note: this was also posted on nikoncafe. I'm looking for a little wider discussion.

-SteveL

 

[Thomas Niemann]

A test I ran a while back... choose

Exporting Files > Archiving

at

http://epaperpress.com/psphoto/

 

[Redcrown]

Smugmug and Mpix make the same recommendation. I refused to believe it, so I sent 8x12 test prints through Mpix at jpeg 10 and jpeg 12. Absolutely no difference in print quality.

 

[SteveLig]

Hmmm. Well, I guess that's good to know. It will save some space and upload time anyway!

Thanks for the replies!

-SteveL

 

[Kim Letkeman]

Has this been other's experience? I'm not sure how you can cut the
file data by half and not be able to detect a visual difference. Am I
missing something here? Does it depend on the scene and what is being
captured? Am I thinking about this correctly?

JPEG is designed to cut file sizes to 1/10 and remain excellent with invisible artifacts. in fact, jpeg artifacts at 10:1 are invisible to sharpening algorithms.

For your reference, FINE on most cams is about 6:1 compression. NORMAL is about 12:1. Pro cams seem to use a bit less compression.

Cutting a file size in half is exactly what happened from FINE to NORMAL. There is virtually no difference between those two. Cut it is half again and you might start to see some issues. 24:1 compression is still good, but you may find a few artifacts in there if you pixel peep.

I use 9 for most of my prints and have never seen an artifact .... color remains very strong as well. You should print a fairly detailed subject at a fairly large size in both compression levels (9 and 10) .... that'll settle the issue for you.

--
http://letkeman.net/Photos

 

[SteveLig]

Thanks for the suggestion, Kim! Sounds like a plan!

-SteveL