[magick-users] IM not filling background in completely black ?

[Chris Howell]

Here's an interesting question.

If I say.

montage *.png -background black output.png

I get the background in my output.png which appears to be black, however when I tell IM to treat black as transparent I get it largely being transparent however occasionally what seems to happen is I get some trace amount of black around my input images that I've montaged, this leads me to think that when I say black being transparent. Which I would assume to be RGB(0,0,0) in some instances my background gets filled in with RGB(1,1,1) so when then it doesn't appear transparent. Is this anticipated ? I would say that the appropriate action would be to use a -fuzz of like 1 or 2% however if that doesn't address my issue, what would your other suggestions be ?

Cheers
Chris Howell
Software Engineer
the PYXIS innovation - Common Ground for Digital Earth
Kingston, Ontario, Canada
w: www.pyxisinnovation.com
p:613-389-6619