Feature
to a document’s output intent dictionary, using the new entry
called SpectralData. The spot colour characterization data
is supplied using the CxF/X-4 XML format using the guide-
lines in I SO 1797 2- 4:20 15 ( h t t p s: // w w w.i so.org /
standard/61503.html). When it comes to file preparation, these are just some of
the features intended to make print production more consist-
ent. As with any step change in file formats, printers should
be testing as they update to ensure that there are no colour
shifts or changes in screening to be re-managed.
If you aren’t familiar with spectral characterization of spot
colours, it uses measured spectral reflectance values and
information on ink opacity. You can learn more about the
power of this feature and see some examples on how it
benefits your printing on the International Color Consortium
website (https://www.iso.org/standard/61503.html). Spectral
data for spot colours is already supported by some
vendors. Security
PDF 2.0 includes many changes that impact how transpar-
ency is handled. The intent is to get more reliable colour
when imposing multiple PDF files from different sources
together, as is common when adding display advertising to
magazines or building catalogue pages. The caveat is that
if you do a lot of this type of work you may notice that your
output results vary in a PDF 2.0 environment.
In an environment where the RIP is at the PDF 2.0 level, it
may automatically apply a CIE-based colour space when a
device colour space is used in a transparent object. In fact,
as PDF 2.0 implementations roll out, you may notice a variety
of subtle changes in your output due to alterations to render-
ing in the specification. The best recommendation is to
download the example files from the PDF Association (www.
pdfa.org) and build a regression testing suite so that you
can identify how your current and future PDF environments
behave.
Another caveat for PDF 2.0 covers halftoning and screening.
Even though these functions have been considered stable
in PDF, the new specification extends options to create a
single PDF file that can select the best halftone for a specific
object when multiple halftone screens are available. There
is also new support for screening transparent objects. These
features may be most useful to printers who specialize in
high-quality flexo printing where halftone specification for
an object is a common part of the workflow.
For those printers who specialize in engineering drawings
and maps, you may have files tagged to use a viewer prefer-
ence key that specify what scaling to use for printing. In PDF
2.0 there is one additional feature that allows for the scaling
factor to be enforced.
PDF 2.0 improves handling of large black areas or featured shadows with Black Point Compensation
22 | May 2018 | GRAPHIC ARTS MAGAZINE
Document-level security is a requirement that PDF 2.0
embraces with gusto. It requires stronger encryption and
has been enhanced to allow Unicode non-Roman characters
for passwords.
Organizations that use the
security features of PDF will
have noticed that keeping
up with the current best
practices has been a strug-
gle. This all changes with
PDF 2.0, which now requires
the new 256-bit Advanced
Encryption (AES 256) and
requires that passwords
used for encryption must be
in Unicode. All other algo-
rithms supported in earlier
PDF and Acrobat versions
are declared as deprecated,
including DES, Triple-DES,
AES-128 and AES-192. If you
have been using the older
AES-256 encryption com-
patible with Acrobat 9, start to make plans for change. Only
the new encryption is supported in PDF 2.0.
The new specification
extends options to
create a single PDF
file that can select
the best halftone for
a specific object when
multiple halftone
screens are available
One thing to remember about password protection is that
even in PDF 2.0, if the file has an owner password but a
blank user password, the file is not protected. If you are
exchanging files with clients, come to an agreement with
them about the level of security they are expecting and
ensure that you have procedures in place to enforce those
security levels.
Accessibility
For many printers, the issue of accessibility is outside the
scope of their environments, but as more direct mailers work
to ensure that their product can reach not only those with
perfect eyesight but also those with sight impairments, the
conversation is changing. Many companies already offer
solutions that use alternative text to tell assistive technolo-
gies what images are in a document, and there are solutions
that can translate PDF files into Braille or voice. PDF 2.0
takes the next step by extending the tagging architecture
and enabling pronunciation dictionaries. This feature is
based on an XML-based W3C format called the Pronuncia-
tion Lexicon Specif ication (ht tp://w w w.w3.org/ TR /
pronunciation-lexicon/ ).
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