4 ms·

Also a paper about halftoning on laser printers: http://users.eecs.northwestern.edu/~pappas/papers/pappas_ist94.pdf http://users.eecs.northwestern.edu/~pappas/

Also a paper about halftoning on laser printers: http://users.eecs.northwestern.edu/~pappas/papers/pappas_ist94.pdf http://users.eecs.northwestern.edu/~pappas/papers/pappas_ist... I have never used a laser printer that did implement anything like this, the usual halftoning sucks. Once I handcrafted a file with a 600 dpi Floyd-Steinberg image (the native resolution of the printer I hadd) and it resulted in much better results, I didn't bother calibrating the gray levels though.

jgneff 9y ago
I came to the same conclusion just this week. I got the best print simply by matching the density of my black and white laser printer with the black dots I wanted it to print. Specifically, I used the ImageMagick operations "-dither FloydSteinberg -monochrome" for more contrast or "-dither FloydSteinberg -remap pattern:gray50" for more fidelity to the original image. I was surprised that the prints were better without adjusting for gamma. If I converted the image to a linear color space before the dither operation, the print came out too dark. I'm guessing that the gamma in the non-linear color space compensated for the dot gain on the printer to cancel out the effect.
- leni536 9y ago
  > I was surprised that the prints were better without adjusting for gamma. Ha, it was the same for me. I used imageworsener where I had to explicitly specify -nogamma for this effect. An other place where wrong gamma handling accidentally works is text anti-aliasing. It turns out that for small font size the wrong handling of colorspace results in more readable text than the gamma-correct method only for dark text on light background [1]. No wonder people don't like to use light fonts on dark background (like terminals). [1] https://www.freetype.org/freetype2/docs/text-rendering-general.html#experimental-stem-darkening-for-the-auto-hinter https://www.freetype.org/freetype2/docs/text-rendering-gener...

jgneff 9y ago

I came to the same conclusion just this week. I got the best print simply by matching the density of my black and white laser printer with the black dots I wanted it to print. Specifically, I used the ImageMagick operations "-dither FloydSteinberg -monochrome" for more contrast or "-dither FloydSteinberg -remap pattern:gray50" for more fidelity to the original image. I was surprised that the prints were better without adjusting for gamma. If I converted the image to a linear color space before the dither operation, the print came out too dark. I'm guessing that the gamma in the non-linear color space compensated for the dot gain on the printer to cancel out the effect.

leni536 9y ago
> I was surprised that the prints were better without adjusting for gamma. Ha, it was the same for me. I used imageworsener where I had to explicitly specify -nogamma for this effect. An other place where wrong gamma handling accidentally works is text anti-aliasing. It turns out that for small font size the wrong handling of colorspace results in more readable text than the gamma-correct method only for dark text on light background [1]. No wonder people don't like to use light fonts on dark background (like terminals). [1] https://www.freetype.org/freetype2/docs/text-rendering-general.html#experimental-stem-darkening-for-the-auto-hinter https://www.freetype.org/freetype2/docs/text-rendering-gener...