Re: PDF color conversion app
Re: PDF color conversion app
- Subject: Re: PDF color conversion app
- From: Henrik Holmegaard <email@hidden>
- Date: Wed, 24 Jan 2001 08:30:41 +0100
"Broudy, David" <email@hidden> wrote:
I'm looking for a standalone batch-oriented app that can take drag n'
dropped (drug n' dropped?) PDF 1.2 containing RGB images and convert to CMYK
preferably using an ICC profile.
PDF 1.2 is not ICC compatible.
PostScript color space specifications in PDF 1.2 are as follows:
a. CMYK is reverse pixel transformed into CIELab D50 (four channel
CIEBasedDEFG CSAs aren't supported).
b. RGB is given a CSA and becomes calibratedRGB.
c. Grayscale is given a CSA and becomes calibratedGray.
(d. CIELab is a subset of CIEBased spaces in PostScript and PDF but I
never heard anyone speak of calibratedLab -:)).
e. Objects may also be specificied as deviceCMYK, deviceRGB and deviceGray.
PDF 1.3 and PDF 1.4 support the device color specification and the
CIEBased color specification. They also support the ICCBased color
space specification.
If you want to look inside a PDF 1.3, try Adobe InProduction. It will
give you the color space specifications per object.
However, InProduction will only give you the numerical co-ordinates
for CIEBased color spaces. Even if you know Photoshop saved out the
ICC working space for ColorMatch RGB as a CIEBasedABC CSA, the name
is gone. This means you can't track the spaces or guesstimate the
gamut volumes you are converting from.
There is a very simple batch function in InProduction. You define an
input hotfolder and an output hotfolder for the current color
settings, and then convert. You can't set up multiple hotfolder
systems etc. Also if you ask InProduction to tag a 40 page PDF 1.3
RGB file with text and lowrez screenshots, it takes 4.5 minutes on a
beige G3. Great software for learning about PDF and for
troubleshooting single files, but way too slow and manual for real
production.
To set up a production workflow with PDF you need a tool like LOGO /
GretagMacbeth iQueue available at Seybold time. It does queues from
hotfolder to hotfolder, hotfolder to printer, printer to hotfolder,
and printer to printer for PostScript, EPS and PDF plus raster
formats TIFF, JPEG, PNG and Scitex CT within the color management
limitations of these respective formats.
--
Henrik Holmegaard
TechWrite, Denmark