Page 201 - Graphic Design and Print Production Fundamentals

Graphic Design 189
style sheets) base, making it easier to produce and distribute data-driven documents for multi-channel
communications.

Output Method

The ‘P’ in VDP stands for printing and is the main output method we will discuss here. However,
document personalization and data-driven communications have evolved to also include email, fax, web
(PURL, personalized landing page), SMS text messaging, and responsive design for various mobile
device screen sizes. With the emergence of quick response (QR) codes, even printed communications
can tap into rich content and add additional value to the piece. In order to take advantage of these
additional distribution and communications channels, a workflow component is often employed.

A key element for optimized print output of VDP documents is caching. This is where the printer’s RIP
caches or stores repeatable elements in print-ready raster format. This means the RIP processes these
repeating elements once, and then reuses these preprocessed elements whenever the document calls for
them. This does require a RIP with enough power to process large amounts of data and resources with
support for the caching scheme defined in the VDP file but, ultimately, allows the printer to print at its
full rated speed without having to wait for raster data from the RIP.

There have been many proprietary VDP file formats that have striven to improve performance of
VDP over the years, but the industry is moving rapidly toward more open standards. PODi, a not-for-
profit consortium of leading companies in digital printing, is leading the way with two widely adopted
open VDP standards. These standards are PPML (Personalized Print Markup Language) and PDF/VT
(portable document format/variable transactional).

PPML

PPML, first introduced in 2000, is a device independent XML-based printing language. There are two
types of PPML: thin and thick. Thin PPML is a single file, with the .ppml extension, containing all the
instructions necessary for producing the VDP document. It does include caching instructions; however,
all resources such as fonts or images are stored externally of the file. The path to these resources is
defined in the RIP and retrieved during the rendering process of the document. Thin PPML is ideal
for in-house VDP development where resources may be shared by multiple projects. These files are
extremely small, however, and network speed and bandwidth may affect performance and are more
difficult to implement if using an external print provider. Thick PPML is a .zip file containing all the
required resources (fonts, images, instructions, etc.). This format makes the file highly portable and easy
to implement on the print device, but it has a larger file size when compared to thin PPML. RIPs that
support the PPML format can import the .zip file directly. Regardless of the type used, PPML benefits
from exceptional performance, an open standard, open job ticketing support (JDF), and overall reduced
file size. To generate PPML, an advanced VDP solution is required.

PDF/VT

PDF/VT is a relatively new international standard (ISO 16612-2) that has a lot of potential. It is built off