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E-Paper Floyd-Steinberg 7 colors


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1 hour ago, MEB said:

Hi @masevein,
Welcome to Affinity Forums :)
Currently we don't support importing/loading colour tables/custom palettes, so this is not possible in Affinity Photo at the moment.

Thanks! Is there a way to reduce the colors to 7 and then I can change the colors to the ones specified in that guide?

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The seven RGB colors in the color table are:

(R,G,B)

0,0,0

0,0,255

255,0,0

0,255,0

255,128,0

255,255,0

255,255,255

 

You can perform Floyd-Steinberg dithering in ImageMagick using the following command:

convert original_image.png -dither FloydSteinberg -remap colortable.gif dithered_image.gif

where "original_image.png" is the full-color image you want to dither, "dithered_image.gif" is the dithered output of the operation, and "colortable.gif" is a gif image that contains 7 patches of color with the listed colors above - it instructs the algorithm to reduce the original image to a dithered one using only those colors.  I have attached a gif (4px wide by 28 pixels tall) of these 7 colors for your use.

I will say that the results appear more "dithered" than the same results in Photoshop with the n color ACT color table in the link you provided.  Reducing the original image to one with 7 colors will not perform dithering, which is an inherent part of the process to maintain the overall appearance of image brightness in the dithered output.  Even if you try to "Posterize" the image to 7 levels, there will be more than 7 colors in the resulting posterized output.

See more here:

https://legacy.imagemagick.org/Usage/quantize/#dither

in the section entitled "Dithering using pre-defined color maps."

 

Kirk

colortable.gif

7color.pngoutput-colortable.gif.774652264fd6a47ce288d11c29c9bc2f.gif

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