[TYPO3-dev] JPEG quality

[Franz Koch]

Hey,

> if you have "color" problems in your jpegs, it is most likely not
> related to quality settings, but due to the fact that they come from a
> source using CMYK color spectrum (as oposed to a RGB spectrum).

that's not what he meant. The JPG algorithm in general (indepented which 
software it uses) has problems with saturated red colors - especially if 
they cover a bigger area on the picture. You'll get really ugly 
deblocking artifacts as well as the regular compression artifacts (but 
these also more intense then on other colors) unless you raise the 
quality level up to around 90 (for imageMagick, for PhotoShop the 
quality level can be lower in general to achieve the same "good" quality).

This is btw. also a big issue on digital cameras storing their photos as 
JPG unless they use optimized algorithms or different formats.

-- 
kind regards,
Franz Koch