[storystarling]

Nice writeup. I've been looking at this for a print-on-demand project and found that physical ink bleed changes the constraints quite a bit compared to e-paper. In my experience error diffusion often gets muddy due to dot gain, whereas ordered dithering seems to handle the physical expansion of the ink better.

[robinsonb5]

> In my experience error diffusion often gets muddy due to dot gain

Absolutely - there's a reason why traditional litho printing uses a clustered dot screen (dots at a constant pitch with varying size).

I've spent some time tinkering with FPGAs and been interested by the parallels between two-dimensional halftoning of graphics and the various approaches to doing audio output with a 1-bit IO pin: pulse width modulation (largely analogous to the traditional printer's dot screen) seems to cope better with imperfections in filters and asymmetries in output drivers than pulse density modulation (analogous to error diffusion dithers).

[zozbot234]

Traditional litho actually uses either lines in curved crosshatch patterns or irregular stippling. Might be doable using an altered error-diffusion approach that rewards tracing a clearly defined line as opposed to placing individual dots or blots.

[PMunch]

Thanks! I would imagine printing on paper would be a completely different ball game. I actually considered scanning the actual epaper display to show each of the dithering techniques in their intended environment as it does change the look quite a bit. From the little I know about typography and things like ink-wells I can definitely see how certain algorithms can change quite significantly. The original post here has a pattern which looks similar to old newspapers, maybe that's worth looking into?