ninjapig1212 wrote on 2021-08-16, 04:29:

Data algorithm methods are beyond my capabilities as of now. I should learn them already.
[...]
There are areas that I want to show with "pattern" (ordered) dithering, they get dithered in photoshop, cut out, and pasted on top of another instance of the same image that was diffusion-dithered. After that, if I notice pixels that I don't like or if I feel more lines are needed, new pixels are painted onto the image.

AFAIK, Photoshop uses this algorithm for arbitrary palette pattern dithering: https://patents.google.com/patent/US6606166
FYI: The patent expired two years ago.

ninjapig1212 wrote on 2021-08-16, 05:53:

Omg I was using the wrong colors this whole time. Thank you for pointing this out. […]
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dr.zeissler wrote on 2021-08-16, 04:56:

The colors are not so good on a real cga-machine.

Omg I was using the wrong colors this whole time. Thank you for pointing this out.

Wrong: FF0000, FFFF00, 00FF00, 000000
Correct: FF5555, FFFF55, 55FF55, 000000

Remeber that this color set is also available: AA0000, AA5500, 00AA00, 000000. This is less bright, has brown instead of "dark yellow", but has a higher saturation on red and green.

Officially, CGA had two "palettes" only (1, 0).
However, there are also two intensity levels available for them (high, low).

Unofficially, there's a third palette, also.

So in practice, there are more different colours available.

Just be aware that the unofficial stuff might be not necessarily supported by all CGA compatibles. 😉

Palettes overview:
https://lospec.com/palette-list/tag/cga

The CGA Compatibility Tester can display those palettes, if memory serves.
http://www.oldskool.org/pc/cgacomp

I checked the pictures converted in GIF with compushow. with "cshow" you can watch the image in all possible ways. (1-4 CGA Pal, Mono-Hires, Plantronics) great image-viewer for low-end.

+1

Real machine 😀

I came across these today - they definitely belong here: https://twitter.com/pinot/status/1426567442466226178 and https://twitter.com/pinot/status/1427678504053792779