Reduce Number of Color Definitions?

[Combs, Richard]

Fred Ridder wrote:
 
> Jack DeLand wrote:
> > I have inherited some docs that have a huge number (dozens) of color
> > definitions, all in RGB values. I want to edit these down to about
10
> > entries that I actually need. Is there a fast and easy way to do
this?
> 
> If these are colors with names something like "RGB256,256,256", they
> are likely to be artifacts from inserting graphics (I think it was
only one
> particular file format and had something to do with the color depth,
but
> that doesn't really matter in this context), and the easiest way to
get
> rid of them is to use the MIF filters to "wash" the document. Use Save
As
> to save the file in MIF format, then open the MIF file and use Save As
to
> re-save it in .fm format. Or if you have a lot of files to clean, you
might
> want to download and install the demo version of Mif2Go and use the
> "Wash Via MIF" command that the tool adds to FrameMaker's File menu.

The source of these is 256-color (8-bit) PNGs. FM adds each of the
colors defined in such a PNG's color palette to its color definitions
list.

As I was writing this, Art responded. No, full-color (24-bit) PNGs
_can't_ cause this problem -- they don't _contain_ a list of color
definitions. In 24-bit graphics, each pixel can have any RGB value (8
bits each for R, G, and B equals 24 bits), so there is no limited
universe of pre-defined colors. 

_Only_ the 256-color (8-bit) PNGs cause the problem. With only 8 bits
per pixel, these graphics can't use just any combination of R, G, and B
-- they're limited to a palette of 256 defined colors. It's these
RGB-value specifications that you see in FM. 

Art is correct that you have to remove the offending graphics to
eliminate the problem, but you need to do the _reverse_ of what he said.
Change your 8-bit PNGs to 24-bit. (There's surprisingly little increase
in size, in my experience.) 

Once the 8-bit graphics are gone, Fred's suggestion of a MIF wash should
remove the RGB color definitions. 

HTH!
Richard


Richard G. Combs
Senior Technical Writer
Polycom, Inc.
richardDOTcombs AT polycomDOTcom
303-223-5111
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rgcombs AT gmailDOTcom
303-777-0436
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