Re: ps to gif?

From: Takeshi Enomoto <eno_at_nyahnyahspammersnyahnyah>
Date: Wed, 6 Sep 2006 09:21:15 +0900

I am not an ImageMagick expert so I expect someone to correct my guess.

The number of colours are reduced to 256.
Chosen colours are not what you expect.

Here are a few things you could try:

1. PNG
Should it be GIF? PNG is a good alternative.
By default, the number of colours does not seem to be reduced.
To limit the number of colours and make a small file,
use -colors <the number of colours> option.

2. Colour profile
You can specify a colour profile with -profile option.
Colour profiles are found in
/Library/Application Support/Adobe/Color/Profiles/Recommended
if you install any of Adobe apps, for example.

I imagine that a profile is specified in a PDF file
so that convert can use this information when choosing 256 colours.
This is completely a guess.

I have not yet used this format but a ncgm converter is provided with

It would be nice if ncl support one of rastered graphic files in the
I use ps when I need to draw a large plot.
PDF files created by ncl is sometimes huge.
Perhaps no compression is used.
PS files are also large but more stable and can be compressed well
with gzip.
Otherwise I use PDF most and covert to to other format as necessary.

Good luck.


> When converting ps files to gif by imagemagick's convert command,
> there is a
> considerable reduction in the color contrast of the images
> (compared to pdf).
> Convert has a -contrast option which is said to be enhancing the
> contrast, but
> I could not see any effect.
> Do you know any better way for this process, which will not
> decrease the color
> contrast? (I am running Mac Os X, by the way)

Dr Takeshi Enomoto
Earth Simulator Center, JAMSTEC

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Received on Tue Sep 05 2006 - 18:21:15 MDT

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