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Subject:Re: Graphics for both PC and Mac From:Max Wyss <prodok -at- PRODOK -dot- CH> Date:Fri, 27 Mar 1998 20:37:18 +0100
I am aware that the formats I recommended do have some platform specific
I should have added to my original message that the flavor for the inferior
platform should be chosen. It does alsw depend a lot on the target output
for the file. The formats I mentioned do work for printing. Others may have
From my experience, the Mac has no problems understanding PC versions; and
it displays them correctly.
The EPS preview is what it says, a preview. Again, I have not yet seen
problems with this preview on the Mac. The main problem with EPS is that
one needs PostScript output devices; however, by using Acrobat as
intermediate, this problem has lost its severity. And the EPS is still the
only vector based file format which is not that platform dependent.
The GIF format is in its use limited because it is an indexed color format.
So, it can not be used for photographic images. There is also the problem
of the palette, which can cause troubles when the document is displayed or
printed. Besides that, GIF is not fully platform independent, as the
Windows system palette and the Mac system palette are not the same. As far
as I remember from the time I was handling quite a few GIFs the two
palettes have about 220 common colors. Then, some software can handle only
8 bit palettes, but would choke on a 4 bit palette.
JPEG is indeed useful ... as long as one knows what one is doing. It is
good for photographic images, but for low number of colors files, it
introduces artefacts, even at the best quality. BTW, there are TIFFs using
JPEG compression schemes.
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Bridging the Knowledge Gap
> For vector graphics use EPS, for bitmaps use TIFF.
> In general, do not use any platform specific formats, such as PICT or
>Admirable advice. The problem is both of those formats (EPS and TIFF) *are*
>platform-specific, though in a very subtle way.
>EPS files are saved with a "preview" image which is used by most
>applications to show you what the image looks like. The package doesn't
>parse the EPS, but rather positions the preview image on the screen. EPS/PC
>uses TIFF for the preview image, EPS/Mac uses PICT, so if you use an EPS
>graphic in one of the many applications which relies on the preview image,
>then you'll only see the image if you're on the same platform that created
>it. Anywhere else, you'll just get a box with an X in it.
>TIFF images are dependent upon the byte-order of the system. JARGON ALERT:
>The two methods are known as "Big Endian" and "Little Endian," taking their
>name from whether the most significant byte of a multi-byte value is first
>or last. That's why Photoshop gives you the Mac/PC choice when you specify
>TIFF. Many other packages only know how to read TIFF files of the same
>byte- order as they are.
>I've found GIF and JPEG to be the most hardy of the cross-platform formats.
>As someone noted, you can set JPEG to be lossless compression. You will
>still get compression, but not the 100:1 compression you often get from
>JPEG. If it's an image you going to be returning to again and again to
>modify or retouch, I'd definitely recommend a lossless compression. OTOH,
>you're not going to make continual changes but rather start from the same
>base image for any adaptations the lossless compression method isn't as
>Chief Managing Director In Charge, Department of Redundancy Department
>Arlen -dot- P -dot- Walker -at- JCI -dot- Com
>In God we trust; all others must provide data.
>Opinions expressed are mine and mine alone.
>If JCI had an opinion on this, they'd hire someone else to deliver it.