[Gimp-user] how to exposing more tiff load options for scripting

[Tim Dickson <tim tree-of-life co uk>]

I am trying to load single pages from multipage tiffs, convert them to 
monochrome (dithered), flatten the image, then save them as single 
monochrome, ccitt group4 tiffs. - all through scripts.

The multipage tiffs contain pages in grayscale and colour which were 
created using the old style (problematic) jpeg compression option.

I have tried other tools, such as libtiff (modified with a patch to 
handle the old jpeg compression), and the latest version of imagemajick. 
Unfortunately they cannot correctly convert the files, whereas gimp can, 
but only one page of the multi-page tiff at a time
(gimp crashes if I load a 5page document (as separate images) then 
convert each image to monochrome,flatten and save in one session)

the scripting function for loading tiffs
file-tiff-load
does not expose the options to load individual pages, or to select 
loading as images or as layers, which the visual file load/import does.

does anyone have any suggestions as to how I can achieve this using a 
script.?
manually is not a problem, but too time consuming for large (eg. 
200page) tiffs.
thanks, tim