Computer Graphics with Photoshop - Misbehaving DCS files

Author

Misbehaving DCS files

Odysseus

2004-09-17, 7:14 pm

Photoshop (CS) v8.0 under Mac OS v10.3.5 on a G4/733 with 1GB RAM.

I recently received for output four CMYK flyers done entirely in
Photoshop (Windows, not sure which version but quite recent), with lots
of layers of type, vector effects, &c. Three of the four were set up at
600 ppi, and the other at 300. After editing the files (adding bleeds,
inserting adjustment layers to turn 100/100/100/100 objects into a
normal rich black, &c.) I saved them in Photoshop format then, as is my
habit, made copies in DCS1 format for output, first downsampling the
600-ppi files to 300. Hoping to get the best possible definition from
the type &c., I checked the box to include vectors.

Each separation of the originally-300-ppi file showed a size of about 13
MB. A little high, I thought (the 'nominal' size of the original being
about 34 MB), but no big deal. OTOH the others weighed in at 45-50 MB
each, despite having been downsampled. Must be the vectors, I thought
.... Well, an imposed file of all four wouldn't go through our ECRM
(Harlequin) RIP, generating a PostScript error. Deciding there must have
been something whacky in the vector data -- I haven't any experience
outputting Photoshop vectors -- I went back to my layered originals,
flattened them (downsampling the three oversized ones to 300 ppi again),
and saved as DCS1 (of course the vector-inclusion option was now greyed
out). To my great surprise, the file sizes were the same as before! And
they still failed to RIP.

Pretty well desperate by now, I opened the DCS files in my old Photoshop
5.5 under Mac OS 9.2 and resaved them in the same format; now they all
showed the expected 8+ MB per plate, and my four-on imposition went
through the RIP just fine.

Any ideas as to what might have been going on here? Are there known bugs
in saving in DCS format from Photoshop 8 / OS X? If so, is it just DCS1,
or DCS2 as well? The latter would be a real problem; while I use DCS1
essentially for convenience, speeding up parts of our workflow, the only
way I know to get arbitrary spot colour plates into another application
is _via_ DCS2, making it essential for some jobs. Or might it be that
for some reason (appearances to the contrary) the flattening (or
downsampling) didn't actually 'take'?

--
Odysseus

WharfRat

2004-09-18, 12:14 pm

in article odysseus1479-at-BE8E1F.13501617092004@news.telus.net, Odysseus at
odysseus1479-at@yahoo-dot.ca wrote on 9/17/04 12:50 PM:

> Photoshop (CS) v8.0 under Mac OS v10.3.5 on a G4/733 with 1GB RAM.
>
> I recently received for output four CMYK flyers done entirely in
> Photoshop (Windows, not sure which version but quite recent), with lots
> of layers of type, vector effects, &c. Three of the four were set up at
> 600 ppi, and the other at 300. After editing the files (adding bleeds,
> inserting adjustment layers to turn 100/100/100/100 objects into a
> normal rich black, &c.) I saved them in Photoshop format then, as is my
> habit, made copies in DCS1 format for output, first downsampling the
> 600-ppi files to 300. Hoping to get the best possible definition from
> the type &c., I checked the box to include vectors.
>
> Each separation of the originally-300-ppi file showed a size of about 13
> MB. A little high, I thought (the 'nominal' size of the original being
> about 34 MB), but no big deal. OTOH the others weighed in at 45-50 MB
> each, despite having been downsampled. Must be the vectors, I thought
> ... Well, an imposed file of all four wouldn't go through our ECRM
> (Harlequin) RIP, generating a PostScript error. Deciding there must have
> been something whacky in the vector data -- I haven't any experience
> outputting Photoshop vectors -- I went back to my layered originals,
> flattened them (downsampling the three oversized ones to 300 ppi again),
> and saved as DCS1 (of course the vector-inclusion option was now greyed
> out). To my great surprise, the file sizes were the same as before! And
> they still failed to RIP.
>
> Pretty well desperate by now, I opened the DCS files in my old Photoshop
> 5.5 under Mac OS 9.2 and resaved them in the same format; now they all
> showed the expected 8+ MB per plate, and my four-on imposition went
> through the RIP just fine.
>
> Any ideas as to what might have been going on here? Are there known bugs
> in saving in DCS format from Photoshop 8 / OS X? If so, is it just DCS1,
> or DCS2 as well? The latter would be a real problem; while I use DCS1
> essentially for convenience, speeding up parts of our workflow, the only
> way I know to get arbitrary spot colour plates into another application
> is _via_ DCS2, making it essential for some jobs. Or might it be that
> for some reason (appearances to the contrary) the flattening (or
> downsampling) didn't actually 'take'?
--
What application are you placing the files into for output?
Are you sending eps or pdf to the RIP?
-
The way to preserve vector data in a Photoshop file
is to save the file as a Photoshop pdf (pdp) file.
-
If you have to work with DCS files to use spot colors ...
place the DCS into InDesign and export the graphic as a PDF.
You will then have a compace spot color PDF
and will not have to screw around with DCS files.
-
Did you comp files contain smaller placed or imported Photoshop pieces?
Did any of those have compression or alpha channels
(especially those 2 thing together)?
-
You maybe should look into feeding your RIP pdf files.
You could be sending the RIP 10 meg files
instead of 200 meg files.

MSD

Mohamed Al-Dabbagh

2004-09-18, 7:14 pm

Odysseus <odysseus1479-at@yahoo-dot.ca> wrote in message news:<odysseus1479-at-BE8E1F.13501617092004@news.telus.net>...
> Photoshop (CS) v8.0 under Mac OS v10.3.5 on a G4/733 with 1GB RAM.
>
> I recently received for output four CMYK flyers done entirely in
> Photoshop (Windows, not sure which version but quite recent), with lots
> of layers of type, vector effects, &c. Three of the four were set up at
> 600 ppi, and the other at 300.

So you say you do color correction and adjust black generation, etc.
Are you authorized to do that by the client? If you are not, why don't
you receive the files in PDF 5 (or higher) format?

> (Harlequin) RIP, generating a PostScript error. Deciding there must have
> been something whacky in the vector data --

How did you decide that? What was the PostScript error?

> Any ideas as to what might have been going on here?

Have you actually made sure that no font is missing?

Mohamed Al-Dabbagh
Senior Graphic Designer

WharfRat

2004-09-21, 4:14 am

> Thanks to you and Mohamed for your suggestions about a PDF workflow &c.
> -- believe me, I've put in many requests to my employer to get some
> PDF-editing software, colour-management tools, in-RIP trapping, &c. in
> here -- but what I most want to understand is why Photoshop 8 would turn
> four 34-MB flattened files into over 600 MB of DCS files that wouldn't
> RIP, and why resaving the files from Photoshop 5.5 apparently solved the
> problem.
--
Sorry not to be more help...
Not much experience in what you are doing.
I would never consider using Photoshop to output a file to a RIP.

MSD