Re: [Gimp-user] Why does saves as JPG default to quality 85?

[Liam R E Quin <liam w3 org>]

On Fri, 2012-03-23 at 17:17 +0100, Olivier wrote:
> The quality rate of JPEG is not a percentage, simply a rate between 0 and 100.

A number in the range 0 to 100 is actually by definition a
percentage ;-)

GIMP tries to detect the compression that was used for the original
image and uses those settings if they're known.

The GIMP numbers are *not* the same as for PhotoShop - 75% in gimp is
not the same as 75% in photoshop.

> To my knowledge, the suggested quality rate is a part of the
> photograph. My camera suggests 90, my daughter's camera suggests 93,
> and I always decrease it to 85, or export to PNG.

I get 97% suggested with my Canon EOS camera.

You should always save to a lossless format such as PNG if you might
need to work on the image again in the future - every time you load and
save a JPEG file the quality is reduced and information is lost.

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/