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SUMMARY: PDF problems on multiple platforms

A month ago, I asked the following questions.
This summary is late, but better late than...

Thanks to:
Michael Richards <michaelr@ind.tansu.com.au>
Peter Spicer <pspicer@dascom.com>
Viktor Haag <viktor@peergroup.com>
"Banttari, Ananda" <Ananda_Banttari@sdsi.com>

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Thomas Michanek, Documentation Manager, Telelogic Tau
Telelogic AB, Teknikringen 9, SE-58330 Linkoping, SWEDEN
PHONE/FAX:  +46 (0)13 200656/212166
EMAIL:  mailto:Thomas.Michanek@telelogic.com
WWW 1:  http://www.telelogic.com
WWW 2:  http://hem1.passagen.se/framers
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> We need to convert our Frame documents to PDF so that they
> can be viewed in Acrobat Reader on both UNIX and Windows NT 4.
> We can distill to PDF on either platform.
> General problem: text and graphics appear different in Acrobat
> Reader on the two platforms. We need them to look as similar
> as possible, regardless on which platform the PDF is produced.
> What platform should we distill on and with which settings?
> FrameMaker version 5.5.3 on both platforms.
> Acrobat Distiller 3.02 on Windows NT 4.
> Printer driver: Distiller Assistant v3.01.
> Acrobat Distiller 3.01 on UNIX (Solaris).
> Acrobat Exchange/Reader 3.01 on both platforms.
> Distiller settings (identical on both platforms): 
>   Compress text and line art, Downsample bitmap images on or off 
>   (see below), Manual ZIP compression, Embed all fonts, Preserve
>   transfer functions, Unchanged color conversion, 3.0 compatibility
> Fonts used: Times, Helvetica, Courier (Type 1 versions)
> Graphics (imported screendumps) are monochrome, grayscale,
>   and color, at different dpi's (72, 100, 150, etc.)
> All documents viewed at 100% scale.

We are now using Acrobat version 3.02 on both platforms to avoid
problems with possible inconsistencies. The monochrome graphics
are XWD files, grayscale/color graphics are GIF files.
Michael Richards said: "EPS is the only file format that all flavours
of Distiller translate optimally into pdf"

> The fonts Times and Courier appear identical on UNIX and Windows,
> but the font Helvetica appear different (without smooth).
> Why does Helvetica look different on UNIX and Windows?
> Note: we embed fonts, but are these fonts really embedded?

The differences in Helvetica could be due to ATM being used or not,
or that the font isn't found in the Acrobat/ATM font database, or
due to differences in the Type 1 definitions. This is a minor
problem, and I haven't spent the time figuring this out.
BTW, file sizes are identical even if all fonts are embedded, so
it seems like Times/Courier/Helvetica are never embedded.

> When viewing a UNIX-generated PDF on Windows, the grayscales
> and colors are rendered differently compared to UNIX.
> The same is true for Windows-generated PDF viewed on UNIX.
> Some grayscales/colors become "dotty" or "patterned" in a
> way that doesn't happen on the other platform. This is
> difficult to explain in words, but very annoying on-screen.
> Is this difference in the Acrobat Readers a known and
> unavoidable problem?

Apparaently, this is a known problem which is unavoidable.
This is not the same as the problem with "fuzzy" screenshots, but
a difference in the "raster quality" of gray and colored areas.
Updating to Acrobat 3.02 doesn't solve this problem.

> When downsampling graphics is turned off, the resulting PDF
> becomes much larger in Windows (as expected). However, on
> UNIX, the resulting PDF actually becomes *smaller* (with
> all other settings being identical in the Distiller).
> We have checked the resulting PDF by zooming in on graphics, 
> and the graphics are really downsampled (or not) as expected,
> on both platforms. Can anyone explain this?

This apparently has something to do with how Acrobat handles
index-colored image formats like GIF on different platforms.
For printing purposes, we need to turn off downsampling, and
then distilling on UNIX is much more effective than in Windows
(when it comes to the resulting file size).

> With smoothing turned on, monochrome graphics at 72 dpi are
> not affected on UNIX, but they become "smoothed" in Windows.
> If you change the scale somewhat, the graphics are not
> "smoothed" anymore.
> Is this a known "feature" and how do you avoid it?

This is apparently another unavoidable feature of Acrobat...

> Other questions:
> Is the used printer driver in Windows a bad choice?
> How do we know what PPD is associated with the driver?

The only way to see the PPD file is to print a test page, but
apparently you cannot change the PPD file once the printer 
driver has been installed...
We have also tried the AdobePS 5.0 driver, without any changes
in the resulting PDF files.

So, we are using Acrobat Distiller 3.02 on UNIX, and have to
live with the platform inconsistencies. It would be nice to
see all these problems corrected in Acrobat version 4.

/Thomas Michanek

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