AuthorTopic: Full Dithering: 24bit->256 colour dithering in the HSV colour space  (Read 8495 times)

Offline happymonster

  • 0010
  • *
  • Posts: 455
  • Karma: +0/-0
    • View Profile
I thought that people might be interested in seeing what you can do with dithering with hues and saturated colours rather than just with different shades. That is not used that much as far as I can see.

Secondly, I think the results are pretty good for a fixed palette, and perhaps naively I thought that artists might be best placed to see that. This is at least in comparison to other fixed palette I've seen. I admit this alone has little practical use now, but I can't help but wonder if it would have been useful when games were restriced to only 256 colours.

Finally, if people can have an in-depth conversation about the technicalities about AA or sel-out, then I would hope to have interest in areas such as this too. :P

Offline Helm

  • Moderator
  • 0110
  • *
  • Posts: 5159
  • Karma: +0/-0
    • View Profile
    • Asides-Bsides
I was very impressed with the downsampling of the Diablo image, true and I did zoom in and pay attention to the technique, for one.

I expect pixel artists to be more interested in techniques and effects they can manually produce though. So if from this as a starting point you develop some manual dithering technique which saturation-slides instead of hue-slides to achieve some effect that is new, I'm sure people will jump on that much more.

Offline happymonster

  • 0010
  • *
  • Posts: 455
  • Karma: +0/-0
    • View Profile
That's also true. I'm not sure how well the latest versions of promotion or photoshop handle colour spaces but if there is no easy way to alter the hue without the luminance also being affected then at least people could pick colours from the palette image I posted, or maybe an expanded image. Then at least they will be able to mix colours with less visible patterning in the dithering (albeit with all monitors and peoples eyesights being different)

I suppose the stumbling block here is that with few colours you want to have a full range of shades, where as this technique lends itself more to groups of identical shades of different hues.

Offline Ai

  • 0100
  • ***
  • Posts: 1057
  • Karma: +2/-0
  • finti
    • http://pixeljoint.com/pixels/profile.asp?id=1996
    • finticemo
    • View Profile
That's also true. I'm not sure how well the latest versions of promotion or photoshop handle colour spaces but if there is no easy way to alter the hue without the luminance also being affected
no, although
LCH color space is capable of altering hue with relatively minor shifts in perceived intensity (much much much lower than HSV, or even HSL)

(that page makes it look a bit more complex than it is. LCH is simply a transform of the LAB colorspace into polar coordinates.)

LAB has the same properties, except you cannot alter hue directly.
Photoshop seems to use LAB for it's Color mode.
Quote
then at least people could pick colours from the palette image I posted, or maybe an expanded image. Then at least they will be able to mix colours with less visible patterning in the dithering (albeit with all monitors and peoples eyesights being different)

I suppose the stumbling block here is that with few colours you want to have a full range of shades, where as this technique lends itself more to groups of identical shades of different hues.
Yes. I've generated an 'optimal' 256-color LCH palette, which matches more the general trend in good pixel art of having every color in the palette be a unique brightness. I've tried arranging it, I think that it's nearly impossible to make a really good palette that does not possess the aforementioned property; I could only arrange it into ramps, but not into exactly-aligned ramps of the same length.



If you insist on being pessimistic about your own abilities, consider also being pessimistic about the accuracy of that pessimistic judgement.

Offline happymonster

  • 0010
  • *
  • Posts: 455
  • Karma: +0/-0
    • View Profile
Now I'm just being silly! Diablo III in 32 colours (amiga style) :P
http://www.retroidea.com/Fixed256/output9.png

Offline Gil

  • 0100
  • ***
  • Posts: 1543
  • Karma: +1/-0
  • Too square to be hip
    • http://pixeljoint.com/p/475.htm
    • View Profile
    • My Portfolio
I'd love to see you do one of these with Arne's palette. Just for giggles :)

Offline happymonster

  • 0010
  • *
  • Posts: 455
  • Karma: +0/-0
    • View Profile
Wouldn't work I'm afraid.. Arne's palette has a full range of shades so that a red say won't have the same luminance as any other hue. This works for 16 colours as a larger range of shades is more important than mixing colours really.

Offline happymonster

  • 0010
  • *
  • Posts: 455
  • Karma: +0/-0
    • View Profile
I just realised I was making a silly error with the de-saturated colours. Now fixed and the subtleness of colours blending into grey is captured much better. This goes some way to avoid having a separate set of desaturated hues and shades. Also made the overall saturation more faithful:
http://www.retroidea.com/Fixed256/output11.png

Also, I managed to squeeze in a few more shades to the 32 colour version, which improves the detail a little. Also improved the hues a little and added the revised de-saturation code:
http://www.retroidea.com/Fixed256/output10.png