640 x 400, 8 colors dithering ?

By AmiMSX

Rookie (21)

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03-02-2019, 19:46

Hi, lately I was looking at PC8801 game's graphics particularly advenure games. I was amazed by the way the designers used dithering to expand the 8 base colors palette (in 640x200). For example, "JESUS 2" has among the best gfx and they look colorful. This dithering technique was also used with MSX2 games. But to me "JESUS 2" (not ported to the MSX 2 as far as I know) is the one which seems the most accomplished due to its level of dithering complexity.

When looking carefully at the dithering method used we can see that it's not only made with simple patterns like : red + yellow = orange, the dithering patterns look way more complex than that.

So I was wondering if the graphic artists draw them manually or if they used painting programs with some kind of algorithms/dithering function, to create all these different color nuances (sometimes they can look like "computerized" dithering Wink ).

Any idea about this ? What do you think guys ?

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By TomH

Champion (327)

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04-02-2019, 13:33

With no experience whatsoever, making a guess, entirely from first principles, I'd assume that art that complicated was painted with a palette of some larger amount of colours, then automatically reduced to 8, using predefined replacement patterns. So not any sort of automatic dithering, just a direct mapping from (source colour, x, y) to destination colour.

I'm guessing this because the dithering looks too consistent to be automatic, but I can't imagine artists sitting around manually painting every pixel given that the game seems to contain a large number of unique full-screen images.

By Grauw

Ascended (8389)

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04-02-2019, 15:34

There's dithering brushes too. Maybe they used automated conversion, but I wouldn't rely on that personally for pixel art.

By TomH

Champion (327)

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04-02-2019, 16:07

A dithering brush and an automated conversion as I described would be exactly the same thing, just that one is a post-process and the other is just-in-time.

That being said, I note that the game also came out for the PC-9801 and the Sharp X68000; likely either guess could be better evidenced by comparing the PC-8801 art to those more capable platforms. Over in IBM PC world, definitely the Sierra games used a process similar to the one I suggested in order to provide art that both comes close to using the full VGA colour range (i.e. 256 colours) while being pattern-dithered down for EGA displays (i.e. the same resolution, but only 16 colours).

By PAC

Guardian (5236)

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04-02-2019, 19:22

There are graphic editors on MSX such as Graphsaurus or Animecha, for example, capable of painting delimited areas with dithering effect. Even you can define a custom design. So, the same for other platforms.

By santiontanon

Paladin (824)

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05-02-2019, 22:30

Dithering was used even in later 16bit games. Deluxe Paint for the Amiga also had a lot of dithering functions to help with this. But at least from the graphic artists I knew back in the day, they used a mix of auto-dithering tools plus manual adjustments later on.