gmic map_clut with black and white film simulation results in red image


(Oliver Urs Lenz) #1

I am trying to apply black and white film simulation to a colour image with the gmic command line tool, but the result is a redscale image (for lack of a better word). I assume this has something to do with channels and image formats. E.g:

gmic sample tiger map_clut fuji_neopan_acros_100

I am new to gmic, and there is probably a simple explanation, but I’ve searched through all the documentation and don’t know what’s causing this.


Red image often means that the channel number is mismatched or mixed up. In the CLI (Version 2.5.0), it is fine. It has 3 channels each with the same values as you would see below if you examined it.

gmic sample tiger map_clut fuji_neopan_acros_100 output tiger~.png

(G'MIC staff) #3

I think this is a bug.
Try removing the file gmic_film_cluts.gmz in $HOME/.config/gmic (Linux) or %APPDATA%/gmic/ (Windows), and try again.

(Oliver Urs Lenz) #4

That wasn’t enough, but when I also removed clut_fuji_neopan_acros_100.cimgz, it worked!

Thanks for the help! Do you have any idea what caused this?

FWIW, I had another bug before this: it wouldn’t output any image, giving me an error about index 1 not being in the range …, -1, 0 or some such. It went away after I started the ui through gmic once.

My version is 2.4.5 and I’m on Ubuntu.


That means that you are accessing list item that doesn’t exist; e.g., if we do

gmic sample tiger

tiger is in the [0] position. We could also access it with [-1] or ., which means the last item on the list. But if we try any other value, gmic would output your error.