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 CAD / Development / 6218
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Subject: 
Re: Substitute Colors for Dithered Colors?
Newsgroups: 
lugnet.cad.dev
Date: 
Mon, 2 Jul 2001 22:45:53 GMT
Viewed: 
422 times
  
Wow, Lars, that was a lot of code to support r = (r1+r2)/2.

The obvious hypothesis would say that the eye performs spatial integration
on the pixels, so therefore values are averaged. I guess I can try it on my
eyes with L3Lab then.

I looked in Foley & van Dam (1995) but they don't discuss color dithering.
There are examples of it in the color chapter, which was written in the last
age of cheap 8-bit video cards, but they only discuss monochrome dithering,
error diffusion, and halftone printing. You'd think they would touch on
halftone CMYK printing theory at least, the way they are going. Anyway,
pixels on screens get short shrift.

I was hoping for some argument that the perceptual equivalent of dithered
colors has a hue dominated by the more saturated color. This might be true
of the average anyway. One could do color space conversions to check the
proof of that.

-Erik



Message has 2 Replies:
  Re: Substitute Colors for Dithered Colors?
 
I think much of the use of dithered colors in LDRAW really paid off when the dithering was used to imply a different texture, such as shiny gold, diffuse rubber, or flourescent colors. I'm currently concerned about what happens to the dithered (...) (23 years ago, 7-Jul-01, to lugnet.cad.dev)
  Re: Substitute Colors for Dithered Colors?
 
Erik Olson wrote... (...) Yeah, it was mainly to ensure that you remember to support the full range of LDraw colors, i.e. also 0x2000000-0x7FFFFFF, but I guess you already did :-) Models built in MLCad may use these colors, and L3P+L3Lab support (...) (23 years ago, 10-Jul-01, to lugnet.cad.dev)

Message is in Reply To:
  Re: Substitute Colors for Dithered Colors?
 
Erik Olson wrote... (...) I use the average of the two colors' RGB. Try it out in L3Lab by toggling the "Dither or blend colord 256-511" button in the toolbar. Here is the code I use for color decoding: /* Return -1 on invalid LDraw color. rgb may (...) (23 years ago, 2-Jul-01, to lugnet.cad.dev)

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