[Gllug] JPEG, GIMP, Macs & colours

[Tethys]

--------

Richard Jones writes:

>The colour balance is completely different.  Can someone clue me in as
>to what part of the JPEG standard / GIMP / Macs / browsers is causing
>this?

Seems to be some artifact of GIMP's JPEG encoding (which is just a
wrapper around libjpg). If you flip the image and save it as a PNG,
then pnmhistmap shows no change from the original image. It could
always just be due to different compression parameters being used.
Do you know a) what was used to create the original image, and b)
the parameters used?

As a general aside, you should be using jpegtran to do operations
like this, as it allows lossless transformations of JPEG image data.
Doing it in GIMP will require reencoding, and thus will be subject
to the additional loss of information that goes with it.

Tet
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