[Magick-bugs] Group4 monochrome TIFF problem

[Mike Finch]

I am using version 6.3.0.

I am attempting to convert a binary TIFF that is in one format into a 
Group4 compressed TIFF.  I never get a Group4 compressed TIFF as output, 
even when I start with one.  I always get a PackBits encoded TIFF as 
output.
I looked at the code and it seems that the function IsOpaqueImage is 
returning TRUE and the TIFF writing function is changing my request for 
Group4 compression into a request for RLECompression (AKA PackBits).

The command line I attempted is as follows:

convert -monochrome -compress Group4 input.tif output.tif

I even tried turning off the matte channel, as in:

convert  -monochrome -compress Group4 +matte  input.tif output.tif

Both yield similar results.

What parameters are required to create a Group4 TIFF?