As part of a larger series on B&W grayscale conversion in GIMP, I wrote a second script that automatically generates layers using each of the commonly defined film emulation channel mixer values...
|Ilford Delta 100||21,42,37|
|Ilford Delta 400||22,42,36|
|Ilford Delta 400 Pro & 3200||31,36,33|
|Ilford Pan F||33,36,31|
|Ilford XP2 Super||21,42,37|
|Kodak Tmax 100||24,37,39|
|Kodak Tmax 400||27,36,37|
A separate layer is created for each "film" emulation type.
If you leave the checkbox for "contact sheet" checked, a new image will be produced with a contact sheet of each of the settings all in a grid for comparison (instead of layers).
On install, the script can be called from the Colors menu:
Colors --> B&W Film Channels...
If you're interested in the full series tutorial, it can be found here: