Legacy ImageMagick Discussions Archive

hi! i'm about to install Imagemagick 6.8.7 , but 6.7.7 is the last version available from both Ubuntu (13.10) and Debian (Jessie, testing) repositories.
Since it seems that i really need 6.8.7 (seems to have the LAB and YUV accuracy that i actually need), how can we install 6.8.7 there?
Is there any ...

v6.7.7 is old. I suggest you upgrade.


I am not sure LAB was clean in that old a version.

From the changelog:

2012-07-02 6.7.8-2 Cristy <quetzlzacatenango@image...>
Change LAB encoding to permit blurring, resize, etc. (signed A and B channel values now stored using a 50% bias)
Additional.. This ...

convert pic1_L.png pic1_A.png pic1_B.png -combine -set colorspace LAB -colorspace sRGB combined.png

I believe this should be -set colorspace LAB before -combine and -colorspace sRGB after the -combine. See http://www.imagemagick.org/Usage/color_basics/#combine_other

convert pic1_L.png pic1_A.png ...

Testing my method on a single sample image, I get no visual difference.

What version of IM are you using, on what platform? I'm using v6.8.7-0 on Windows 7.

Synaptic says 8:6.7.7.10-5ubuntu3 - it's on Lubuntu 13.10
(i also have Crunchbang-Jessie installed on another partition, i didn't tried ...

This is wrong:
convert pic1_L.png pic2_A.png pic2_B.png -set colorspace LAB -colorspace RGB -combine combined.png
It should be:
convert pic1_L.png pic2_A.png pic2_B.png -combine -set colorspace LAB -colorspace sRGB combined.png
You need to combine before changing colorspace, and change it to ...

hi! i'm struggling on combining, for example, L channel from picture1 and AB from picture2, in a picture 3 - how can we do it?
the idea is copying the luminance from one picture, and the chrominance from other, both in the same pixel size

i tried this, but the result is really weird

convert pic1 ...

do someone know how can we convert pictures to Amiga HAM-6, EHB, HAM-8 (iff ilbm), and NEC-PC88 .mag format? thanks!

Do someone know how can we do chroma key on imagemagick?
This would be like generate a third picture, from two source pictures (one as background, and another for the above 'layer' using blue or green as transparent colour )
http://en.wikipedia.org/wiki/Chroma_key explains a bit better what it is ...