NSImage: Creating 1bit BW Images

FROM : Alex v.Below
DATE : Fri Apr 29 11:47:57 2005

Dear List,

I am looking to create TIFF files from an NSImage which are suitable
for efax(1) and efix(1). It appears that these TIFFs must be 1 bit per
sample, 1 sample per pixel.

I might have been trying too much not so see the obvious, but I have
not found a "native" way in Cocoa of doing so. Of course I tried,
setBitsPerSample, I tried the Monochrome NSImage Sample Code, and I
even have code to generate a 1bit image using a threshold value.

So my - hopefully - question is: Have I overlooked the obvious way of
doing this?

Or am I on the right track and I need to implement a dither-algorithm
myself?