VDP is a direct outgrowth of
digital printing, which harnesses computer databases and digital print devices and highly effective software to create high-quality, full color documents, with a look and feel comparable to conventional
offset printing. Variable data printing enables the
mass customization of documents via digital print technology, as opposed to the '
mass-production' of a single document using
offset lithography. Instead of producing 10,000 copies of a single document, delivering a single message to 10,000 customers, variable data printing could print 10,000 unique documents with customized messages for each customer. There are several levels of variable printing. The most basic level involves changing the salutation or name on each copy much like
mail merge. More complicated variable data printing uses 'versioning', where there may be differing amounts of customization for different markets, with text and images changing for groups of addresses based upon which segment of the market is being addressed. Finally there is full variability printing, where the text and images can be altered for each individual address. All variable data printing begins with a basic design that defines static elements and variable fields for the pieces to be printed. While the static elements appear exactly the same on each piece, the variable fields are filled in with text or images as dictated by a set of application and style rules and the information contained in the database. There are three main operational methodologies for variable data printing. In one methodology, a static document is loaded into printer memory. The printer is instructed, through the
print driver or
raster image processor (RIP) to always print the static document when sending any page out to the printer driver or RIP. Variable data can then be printed on top of the static document. This methodology is the simplest way to execute VDP, however its capability is less than that of a typical
mail merge. A second methodology is to combine the static and variable elements into print files, prior to printing, using standard software. This produces a conventional (and potentially huge) print file with every image being merged into every page. A shortcoming of this methodology is that running many very large print files can overwhelm the RIP's mad processing capability. When this happens, printing speeds might become slow enough to be impractical for a print job of more than a few hundred pages. A third methodology is to combine the static and variable elements into print files, prior to printing, using specialized VDP software. This produces optimized print files, such as
PDF/VT, PostScript or
PPML, ==Software and services==