Legacy ImageMagick Discussions Archive

When I upgraded my Linux system I discovered that
the version of IM that came with it (6.5.4) performs
the operation "convert someimage.cr2 outimage.png"
differently than it did with an earlier version.
Apparently, the output image is now contrast-enhanced
and red-enhanced. This is not what I want. RAW decoding
is supposed to be neutral. How do I restore this principle?

It is possible that the problem exists in the PNG encoder.
What happens if you convert to a different format such as PPM
or JPEG?

Can you try IM version 6.7.0 or later and see if the problem
persists?

Also try saving to a different format and displaythign the result. Such as MIFF. This will let you know if it is a input coder problme or output coder problem.

NOTE input coder is a delegate, call to the "dcraw" program. This may also have changed.

It gets worse: I decided to ignore the
differences in RAW decoding and continue
on with the series of convert operations
involving an affine transform and cropping
in the work sequence I do on my images.
The result: comparing IM 6.5.4 and the
earlier one, even the geometry is now different.
The same input image ended up being cropped
differently. I guess I might as well move
on to the very latest IM.

Post the command line that is causing trouble with cropping. You may like to upgrade as there have been significant improvements to IM. Perhaps your command line was incorrect, but IM was letting it get by. I just saw a case of this recently reported on an older IM where negative offsets were used for -extent and the result was the same as positive offsets as they should be specified. But the negatives did not work in current versions of IM, only the old one.

P.S. DCRAW seems to be often upgraded and IM has been keeping up with that as far as I know. So if some error is in a particular version of DCRAW, you may be suffering from that. see all the changed versions of DCRAW at viewtopic.php?f=3&t=11183&hilit=DCRAW&start=15

Their was a MAJOR changes made in the distortion EWA filter all through v6.6.4 point releases, which removed the 'fuzziness' that was inherent in the original implementation of elliptical filters, as well as various bug that was being hidden by that fuzziness.

Announcement: viewtopic.php?f=4&t=17062

Details: viewtopic.php?f=2&t=17061

Essentually EWA distortions is now working properly as it was originally intended. So much so that we no longer use a Gaussian resampling filter, by default but a variation that like the normal 'resize' is very similar to 'Mitchell'.
You can now even directly compare images that have been resize using 2-pass orthogonal resize, and 1-pass cylindrical distortion. http://www.imagemagick.org/Usage/resize/#distort_resize and get better results!

An upgrade is recommended.

ASIDE: note also that as of IM 6.7.1 IMv6 developement has slowed, while core developers concentrate on major changed needed to generate IM v7 (alpha) with multi-channel, handling, and an improved 'script or pipeline feed' CLI interface. For the proposals that are being implemented see http://www.imagemagick.org/Usage/bugs/

It is thus likely that some version of IM v6.7.X will become a 'stable' release with only bug fixes being applied.