[Image-SIG] Converting from 24-bit RGB to Black&White
fredrik at pythonware.com
Thu Mar 2 22:44:10 CET 2006
Alexander Belchenko wrote:
> PIL-Handbook.pdf (for version PIL 1.1.3) description of method
> "im.convert(mode) => image" claims:
> "When translating a greyscale image into a bilevel image (mode "1"), all
> non-zero values are set to 255 (white). To use other thresholds, use the
> point method."
the 1.1.3 handbook is incorrect. here's the corresponding text from the
"When converting to a bilevel image (mode "1"), the source image is
first converted to black and white. Resulting values larger than 127
are then set to white, and the image is dithered. To use other
thresholds, use the point method."
(from http://www.effbot.org/imagingbook/image.htm )
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