Image conversion to Grayscale using ImageMagick is very dark

image-processing imagemagick grayscale brightness monochrome
halloleo picture halloleo · Mar 14, 2013 · Viewed 9k times · Source

I converted a bunch of "normal" JPG photos via

convert infile -colorspace Gray outfile

to monochrome. However the result is for all images very dark. Here a sample conversion: original photo and converted monochrome image.

Is there a better way to convert a photo-realistic image with ImageMagick to gray-scale?

Answer

Mark Ransom picture Mark Ransom · Mar 14, 2013

The documentation states that when changing the color space, the colors are converted from their original gamma to linear before the conversion. You need to convert them back to an appropriate gamma.

convert infile -colorspace Gray -gamma 2.2 outfile

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