Re: problems with eps
On Sun, May 29, 2005 at 05:30:20PM +0200, Felix Natter wrote:
> when I try to save this file:
> http://home.t-online.de/~fam.natter/prosper/LDCLogosm.gif
> as .eps (for inclusion in LaTeX-document), the resulting .eps
> looks unsharp:
> http://home.t-online.de/~fam.natter/prosper/LDCLogo.eps
I don't think there's anything wrong with the EPS file. Your GIF is
only 150x80 pixels in size, so the resulting EPS file will certainly
not look any better than the original :)
In PostScript, rasterized images are embedded simply as is (no
vectorization attempts are being made), and that's exactly what
happened. Any perceived 'unsharpness' stems from rescaling/resampling
effects that occur when looking at the image at different sizes -- i.e.
ghostscript, acroread, etc. will most likely _not_ show the image
representing 1 image pixel as 1 screen pixel...
In case you don't believe the actual image is still the same in the
EPS, try the following:
* load the GIF in Gimp and zoom it up to 400% (view->zoom->4:1)
* uncomment line 16 in the EPS file as follows (removes margin offset)
% 14.173228346456694 14.173228346456694 translate
* then display it with ghostscript like this
$ gs -dDEVICEWIDTHPOINTS=150 -dDEVICEHEIGHTPOINTS=80 -r288x288 LDCLogo.eps
Now you should have two windows of same size where each image pixel has
been magnified to 4 screen pixels (in both cases), and you can easily
verify that they're very much the same -- at least that's what they
look like to me... ;)
To achieve better results for printing, you'll probably want a better
image resolution to start with. In case you can't get at one, the best
results will be achieved, if you at least make sure that 1 image pixel
will be represented by 1 halftoning cell when printed. Unfortunately,
that's not always as easy as it sounds, 'cos quite a number of things
do come into play here... (and it would get even more complex if you
plan to print indirectly via PDF).
Feel free to contact me off-list if you need to go that route -- but as
I said, a better original image resolution would definitely be preferable.
>
> When I try to embed the .eps in a LaTeX-presentation, it looks
> even worse (the white background is semi-yellow):
Not sure what further processing steps LaTeX has applied here... the
final result looks somewhat like a smoothed, low quality JPEG to me.
I'm afraid I can't help with this problem...
Cheers,
Almut
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