Legacy ImageMagick Discussions Archive

For some TIFF images, a convert such as:

convert -monochrome DSCF0002.tif test_ren.tif

gives a white-only output. The same happens with:

convert -threshold 0 -verbose DSCF0002.tif test_ren.tif

whereas this command gives a correct output:

convert -threshold 50% -verbose DSCF0002.tif test_ren.tif

So it looks like the auto-threshold does not work for this group of images. An example of such problem images may be found at:

http://folk.uio.no/oeide/DSCF0002.tif

Version info:

Solaris
Machine hardware: sun4u
OS version: 5.8
Processor type: sparc
Hardware: SUNW,Sun-Fire-880

> convert --version
Version: ImageMagick 6.2.9 09/15/06 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2006 ImageMagick Studio LLC


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Regards,

Øyvind Eide

-monocrome don't work for all images.
Look at IM Examples, Two Color Quantization
http://www.imagemagick.org/Usage/quantize/#colors_two
for a alternative technique.

PS: place the operator AFTER reading the image in, not BEFORE. Yes it works, but only for one operation. More than one will not be ordered correctly.

Thank you very much, the problem is solved.

No bug after all


Regards,

Øyvind Eide