EPS vs TIFF file formats (non-vector)

[Jay Smith <jay@xxxxxxxxxxxx>]

Steve (and Don),

There are advantages (two, at least) to saving images in EPS file
format instead of TIF (TIFF) format.  

1) Even though EPS files are usually 2x the size of TIF, they will
often load and show on the screen faster (especially if the EPS is
made with a 1-bit preview instead of an 8-bit).  This is significant
if you have a page with a 4 MB image on it and you are either loading
a tiny 1-bit preview or your are loading ALL 4 MB.  I vote for the
faster.

2) Applications (such as Framemaker) usually read and *interpret* all
the image date of TIF files.  However, since the applications don't
(or usually don't) read the actual image data of EPS, they can't screw
it up -- the only read the header and preview.  Otherwise the
"interpretation" of the TIF files can cause the quality of your
printed output to vary from application to application because the
each application could/does handle ripping the TIF image data
differently.

The only disadvantages that I have encountered (and I am sure there
are more) is that a) in my experience, NON-postscript printers don't
know what to do with EPS images and 2) EPS files tend to be twice the
size, even with the most compact encoding.

However, for portability, now and in the future, EPS gets my vote over
TIF.

NOTE 1: I used the phrase "non-vector" to describe the type of EPS
FILE of which I am discussing the FORMAT.  An EPS-format file may
contain an image of any number of types, including vector (i.e.
typical Illustrator, etc.), bitmap (I refer to black/white 1-bit "line
art"), grayscale, etc.  When I discuss EPS, I am discussing the FILE
format/packaging, etc., not the type of image data.

NOTE 2: If you have EPS-format files that contain non-vector images,
but which do not have previews attached, you can open the files in
Photoshop, SaveAs (you can use the same file name or a new file name);
in that process select either 1-bit or 8-bit previews.  Note that
8-bit previews require a lot more time to load in applications such as
Framemaker and thus perhaps more horsepower in a production
environment.  We use only 1-bit previews and don't mind if they look
terrible on screen.

NOTE 3: In that same resaving (SaveAs) process, you are also given the
choice between BINARY or ASCII encoding of the EPS file.  Proper
selection is critical!  Use of binary encoding will significantly
reduce the size of your EPS files (though they are still twice the
size of TIFs).

First of all, one assumes that you are printing with a Postscript
printer.  (Good luck, otherwise.)  On Win95, anyway, in the driver
setup for your printer there should be a Postscript (tab), Advanced
(button).  Go there and you fill likely find an option for TAGGED
BINARY communications.  ON CERTAIN TYPES OF NETWORKS, if you set your
EPS encoding to "binary", IT IS CRITICAL THAT THIS "TAGGED BINARY" BE
ON/CLICKED.  OTHERWISE YOU CAN TRASH THE NETWORK IN A BIG HURRY.  I've
done it any number of times.

Secondly, on some networks (for example, older Unixware [less than
2.1.2, I think]) or possibly with some printers' network boards, using
the binary encoding may simply not be an option.  

The moral is that before creating lots of TIF or EPS non-vector image
files, you would do well to test the different options and then
announce a *standard* that is expected.  While there is significant
potential to (increase speed AND improve portability and print
consistency) OR (reduce storage space), there are risks that must be
tested on your network with your printers.  Note that even if *you*
are proofing the image files on a directly PC-connected printer, their
final use (such as is ours) may have the files being directly printed
(lp) from a network server as Postscript files -- and your SysAdmin
will not be pleased to have to reboot *his/her* network a few times
before discovering what *your* problem is.

-- 
Jay Smith

e-mail: jay@jaysmith.com

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Steve Evans wrote:      <Blueworld Acrobat List>
> 
> Don,
> 
> Thanks for the info. Regarding your comments:
> 
> (1) If you have them in TIF format saving them in EPS format won't do you
> any good since the imagine isn't in vector format..you're just
> encapsulating it with additional information (which can have some
> advantages for highend printing). Your EPS format is not the same as
> saving an Illustrator document in EPS format (which basicaaly appends the
> preview to the illustrator portion).
> 
> > "Remember True Type fonts are NOT embedded in PDF files ONLY PS"
> 
> Actually, no.
> 
> That may true for Windows users (actually if you have TT fonts using
> Windows it converts them to T1 fonts to embed them). Mac users can embed
> Truetype fonts. Form the Mac manual "If, however, you print to a
> PostScript file on your hard drive, the TrueType fonts will remain
> TrueType fonts in the PostScript file and also in the PDF file" (where
> this may be a problem if you sent a file with TT fonts in it to a highend
> press that doesn't have a TT rasterizer it can't print the fonts).
> 
> Cheers,
> 
> ...Steve
> 
> >Steve:
> >
> >1. Always capture in TIF format. Then make sure compression settings for
> >graphics are off in Distiller. I have tried saving in TIF then converting
> >to EPS
> >before distilling and I did NOT notice any improvement. If printing via
> >postscript
> >the results will be beautiful.
> >
> >2. Remember True Type fonts are NOT embedded in PDF files ONLY PS. So if
> >the font is absent from the user's system Acrobat will substitute.
> >
> >Don Lawson
> ><dclawson@enter.net>
>

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