[magick-users] Watermark

[Fred Weinhaus]

For 8-bit grayscale use -colorspace gray -depth 8

For fewer grayshades add to the above -colors XX




For 2-bit b/w use any of the following:

-threshold XX%
-monochrome
-type bilevel
-colors 2 -colorspace gray  (possibly add -type bilevel)

see
http://www.imagemagick.org/script/command-line-options.php
http://www.imagemagick.org/Usage/quantize/#two_color


I also have several automatic thresholding scripts at
http://www.fmwconcepts.com/imagemagick/index.php




>Thank You for these hints.
>It worked fine on my Linux. I only have the problem, that the output files
>are quite large. I found the same problem with  convert, where all the files
>are in 64bit color depth. Even if I give the parameter -depth 4 the files
>are smaller, but 32 bit.
>
>Can you give me a hint, how I can get at least 8 bit (256 grayscale) or
>better 2-4 bit (black white)?