: Prevent white border effect when converting an image to grayscale with ImageMagick For printing images on a Epson TM-T88v receipt printer, I had to convert a PNG file to a 4-bit grayscale PNG

@Kaufman565

Posted in: #ColorConversion #FileConversion #Imagemagick

For printing images on a Epson TM-T88v receipt printer, I had to convert a PNG file to a 4-bit grayscale PNG by using ImageMagick.

Using the following command I'm getting pretty good results except of a white border around certain parts of the converted image:

convert test.png -depth 4 -colorspace gray -define png:color-type=0 -define png:bit-depth=4 test-4bit-gray.png


Original input image:



Converted image:



If I use Epson's native JS library to convert PNG images to 4-bit grayscale I get following result which looks way smoother:



Which ImageMagick options could help me to avoid the white border around the heart eyes of the Emoji or make it to look smoother at all?

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