Graphics Programs Reference
In-Depth Information
building custom profiles, producing CMYK conversions, or supplying
lose color proofs, be sure to charge your clients a reasonable fee for these
services.
What Is an RGB Pipeline?
I discussed the advantages of using tagged RGB files within page layout.
This makes sense since it's common that a designer might output a com-
posed page to a proofer, perhaps to their desktop printer, a contract proof,
and then to one or more presses. The key to an effective RGB pipeline is
having tagged RGB images There are several problems that can arise using
this pipeline. Does the page layout application support color management
on an element-by-element basis? Can the user view the images and other
elements accurately? How will the conversions to the final output device
be conducted? One of the biggest issues is not having the ability to see
the color until a print actually is created.
PDF
One emerging technology that might solve many issues in providing
output-ready files for print is PDF (Portable Document Format). Color
management in PDF is still a moving target. There are numerous speci-
fications of PDF including those designed for print and reproduction
pipelines such as PDFX1a, PDFX3, and so on. Some of these flavors are
actually restricted subsets of PDF, intended to make the usage and sub-
sequent output of these PDFs easier on the printer. For example, PDFX1a
will handle only CMYK data, whereas PDFX3 allows elements to be in
RGB or LAB. We could say that PDFX1a doesn't support color manage-
ment since by the very design, CMYK is mandatory. Images and other
elements must be in that color model or the PDF will not be distilled from
the original data.
Restricting the color model of a subset of PDF ensures that the sup-
plied PDF to the printer has all the necessary elements for printing. This
frees the printer from receiving files they can't output. This saves time a
printer has to spend inspecting files to ensure they are output-ready; a
process known as
preflight
. Color-managed PDFs can be produced in
a number of ways and Acrobat Distiller version 6.0 has color settings that
should be familiar to Photoshop users. In fact, color settings created in
Photoshop can be shared and loaded into Acrobat Distiller as seen in Fig.
7-14. There are a number of ways to create a PDF. Thus color manage-
ment of the elements being placed into this format can be affected by the
host page layout application. Other problems arise when a page or
number of pages all have elements in different color models like RGB
and CMYK that are untagged.
I'd encourage photographers and just about anyone other than a ded-
icated color geek or expert printer to be very careful in dealing with
