Jpeg compression - best compromise between image quality and filesize

[tbm]

By default I've always saved my processed jpeg images at max. quality (12 in Photoshop) giving 10Mp images that are usually 6-8Mb in size.

I've noticed that saving as jpeg quality 8 images cuts the filesize by around 75% to 1.5-2Mb, with no apparently visible loss of quality.

For the sake of HD space I'm considering using jpeg 8 in the future and re-saving all my old images.. I'll still have the original 16 bit files so it's not like I'll be irretrivably losing data.

What quality setting do you all use? How low can I go before I start seeing artefacts?

Cheers

 

[Chappers]

It all depends on the subject matter. You'll generally see artifacts on items that tend not to be horizontal. The old rule of thumb that I was brought up on was that a JPEG compression that reduced the file to about 10% of its original size, was generally OK.

As you've got the original 16 bit files I wouldn't worry, you've got the originals to fall back on anyway.

In fact as you are saving the originals as 16 bit ( I assume TIFF) then why bother with JPEG's anyway, except for exporting. In fact you might want to save as RAW as this will probably be smaller than the 16 bit files and hold all the data !

 

[tbm]

Cheers Chappers.

Presumably when you say "original size" you're referring to an uncompressed 8 bit file.. I'll have a fiddle with some of the higher compression settings and look for artifacts as you describe.

As you say Jpegs are only there to make the images accessible; either when supplied on CD or published on the web.. I'm saving 16 bit files as .psd, only because these in low compatability form are significantly smaller than equivalent Tiffs.

Never thought of saving everything to the original RAW file - although I'm not sure how I'd go about this as I can't edit RAW in photoshop as I have an older version..