Re: Graphics file formats

["Craig Ede" <craig.ede@xxxxxxxxxxxxx>]

Dov,

While we are on the subject. We have a problem where TIFFs occasionally invert, particularly when they have come from Visio. We don't see the problem when we open the files on PCs, but it happens only the UNIX Solaris machines (the files are copied in). Since our Visio users work on PC and we generate the books on Solaris machines this is a hassle for us. [I have requested that Vision users saveAs PCX and this seems to work.]

Any workaround or tool that will "correct" the problem on the UNIX side, where most of our work and the final document handling is done. 

Thank.

Craig
Los Jugadores Bazutadores

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Subject: Re: Graphics file formats
From: Dov Isaacs <isaacs@Adobe.COM>
Date: Wed, 21 Jul 1999 16:46:40 -0700

Roger,

What you report is very inconsistent with what we know and see here.
A sample that I had of a monochrome line art bitmap (1 bit per pixel)
resulted in a 360Kbyte TIFF file, with LZW compression ON. Saving as
a GIF file resulted in a 377Kbyte GIF file. The GIF file didn't lose
data, but "scaled" the dimensions to match 72dpi. Also, the GIF file's
colorspace is not monochrome bitmap, but rather, indexed color (i.e. RGB)
with two defined colors.

My best guess is that your TIFF file was not saved with the compression
option and/or you have an image pattern that is highly random and severely
defies the standard TIFF compression. (On the other hand, if in fact your 
TIFF file was compressed, but you downsampled to get GIF at the same size 
at 72dpi, you are very lucky that the print image had any usable quality!)

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