Re: Convert 3200

[nathan@visi.com (Nathan Mates)]

In article <3445FB74.1EF7@monmouth.com>,
Daniel Webster  <dwebster@monmouth.com> wrote:
>My prinipal use for Convert 3200, at this point, is not so much to
>produce 3200 colors pictures, but to produce 256 colors pictures for a
>game port.  So my comments are primarily for the 256 colors mode rather
>than the 3200 mode.  I would be very happy to send you the pictues that
>I am converting.  The originals are 256 colors, not millions of colors.

   You will need to understand how 256 color images work on the GS
before you can blindly expect a 256 color image to look much better
than a 16 color image. In 320x200 mode, each scanline supports only 16
distinct colors in a palette. That is imposed by the hardware and not
going to change.

   However, in hardware, you are given 16 palettes to work with out of
the box. By simple math, there are 256 possible colors that you could
work with. But, any colors that need to be used in each of the
palettes cuts down your possible usage. If, say, you make sure that
there's a black and a white in each of the palettes, you're down to
14*16+2 or 226 colors. Any more shared colors will start dropping the
possible colors down even more.

   Since palettes are assigned on a scanline by scanline basis, you'll
find the most use for them if you pictures have a lot of difference
vertically. A lot of games had horizontal score bars with their own
palettes, etc. One recommendation for now is to convert as many
distinct sections as possible with their own 16-color palette and
merge them on the GS side. Photoshop has a bit of an adversion to
palettes in general, but with some work, you can browbeat it into
producing things. Keep around the source art in the best resolution
and colors possible so that you can trivially reconvert it later if
you need to mess with the palette.

   There are ways to work around the GS limitations if you think a
little and design *for* them, instead of trying to make the GS fit
your preconcieved ideas of design.

Nathan Mates
--
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