How to convert a photo to a black and white image by ImageMagick?
Solution 1
According to this forum post:
However, if you want two colors only (black and white), then you need to threshold. For example, to select the color where above will be white and below will be black.
convert <input> -threshold xx% <output>
where xx is in range 0-100 (for percent).
Solution 2
Dithering is clearer and more fax-like than a threshold cutoff:
convert <input> -monochrome <output>
For a less contrasty but more information-preserving kind of dithering, use:
convert <input> -remap pattern:gray50 <output>
Solution 3
According to this answer here:
If you have imagemagick installed:
true grayscale only:
convert source.jpg -colorspace Gray destination.jpg
true black and white:
convert source.jpg -monochrome destination.jpg
separate into gray channels:
convert source.jpg -separate destination.jpg
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ohho
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Updated on September 18, 2022Comments
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ohho over 1 year
How can I convert a JPEG photo to black and white (not grayscale) image like output of a FAX scanner, by ImageMagick?
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Ciro Santilli Путлер Капут 六四事 over 8 years
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Ciro Santilli Путлер Капут 六四事 over 8 yearsNo ImageMagick requirement: superuser.com/questions/75373/…
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David Fraser over 8 yearsNote that if the output looks low-quality, you may need to set the density higher using the flag
-density 150
(the 150 is a dpi value) -
SuperSafie almost 3 yearsGood answer as it gives 2 options that produce different output and you can choose the best result