Re: PDF problems on multiple platforms

[Michael Richards <michaelr@xxxxxxxxxxxxxxxx>]

<heavily snipped>

> > You omit here a most important fact: what is the graphics file format of
> > imported bitmaps?
>
> I didn't think this would matter, as the graphics are copied in and
> stored within FrameMaker, but:
> - monochrome screendumps are originally in XWD format
> - grayscale and color screendumps are originally in GIF format

It does matter because (1) indexed colour files always get translated to
either 8-bit (greyscale) or 24 bit (colour). And file formats appear to be
treated differently (this is only an empirical observation. For example,
single bit eps files printed from from Frame and distilled get to be single
bit images in pdf, while single bit tifs get to be greyscales! Wots going on
here!

> > > The fonts Times and Courier appear identical on UNIX and Windows,
> > > but the font Helvetica appear different (without smooth).
> > > Note: we embed fonts, but are these fonts really embedded?
> >
> > BTW you can check if the font actually has been embedded by going to
> > File:Info:Fonts, which brings up a list of all fonts in the pdf file.
>
> I didn't think the fonts would be embedded, since I've read somewhere
> that Times/Helvetica/Courier are never embedded, but the font info
> lists *all* fonts in the files. The lists are slightly different in
> the Windows and UNIX versions of the PDF file, though.
> This is, however, not a big issue.
>

You can force them to be embedded with the include fonts setting in Distiller
which has 2 degrees of freedom:a) whether to include the "Standard 35" or not
and
b) whether to include subsets or the whole font glyph set. ("Subset here
means that if the ps file has less than 35% of the entire glyph set used,
only the glyph definitions actually used will be bundled into the pdf file.)

> > > 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.
> > > Is this difference in the Acrobat Readers a known and
> > > unavoidable problem?
> >
> > Unavoidable. Sorry.

> So you don't think that this problem is due to what Peter Spicer wrote:
>
> > you have a BIG problem using version 3.01 of Acrobat Reader
> > and Exchange. Version 3.01 has a well-documented problem with its
> > graphics rendering engine that is the cause of much of the fuzzy
> > screenshot (raster graphic) problems people have been describing on
> > this list. This, of course, is assuming they have used the proper
> > Distiller Job Option settings for lossless compression . . .

Windows stuff only. Mac and Unix unaffected.

> But the problems are not with "fuzzy" screenshots, but a difference
> in the "raster quality" of gray and colored areas.

Quite so.

> > > 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).
> >
> > BUT, if you downsample, Distiller essentially takes four pixels and
> > renders them as one pixel. The image therefore gets fuzzy (i.e. is
> > "anti-aliased). That means that Distiller no longer detects the image to
> > be a screen grab and turns it into a jpeg. jpegs can only be greyscale
> > or 24-bit colour. The jpeg version will tend (for screen-grabby stuff)
> > to be bigger than the LZW version.
>
> But why does this then only happen on one of the platforms???
> And we have specifically specified ZIP compression for all graphics.

Weird, isn't it! Why, oh why!!! I ask myself that often! BTW I do not agree
with Mr Gold. Forcing ZIP (aka LZW compression) is NOT a good choice. But he
has made this from the pov of a Windows user. Thank heavens I am not one of
these!

> > UNIX will turn grey tifs into 8 bit images (greyscale) while
> > other Distillers (Mac, definitely, Windows too?) turn all tifs into
> > 24-bit, resulting in file bloat.
>
> We don't use TIFF, so that cannot be the reason.

Same principal. EPS is the only file format that all flavours of Distiller
translate optimally into pdf.

> > > Is the used printer driver in Windows a bad choice?
> >
> > Never use the out-of-the-box PostScript driver from MS.
>
> We don't, we use the Distiller driver provided by Adobe.
> But I guess we should be using AdopePS 5.0.1 instead?
>
> Thanks and keep the advice coming,

And thank you. Now, I must get back to the grindstone.

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