Harlequin VariData
This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP.
The advent of variable data jobs means that many parts of a printing job remains constant with other parts, such as text, being changed for each print. Thus, time savings can be made by processing the constant areas only once, especially if the constant area is a large graphic. This is the idea behind the Harlequin VariData (HVD) feature. The RIP detects constant areas within a PDF file, retains them and then re-uses them as necessary.
Any PDF file with pages that share raster elements and have marks that change from page to page should be accelerated by this optimization in the RIP. The RIP scans the PDF for such pages, RIPs the shared raster elements once, and then retains them for use on subsequent pages with the same raster elements.
HVD intelligently identifies graphical elements and groups of graphical elements and groups of graphical elements that are used together multiple times. In doing so it can make use of the “hint” attributes defined in ISO 16612-2 (PDF/VT). Specifically, GTS_Encapsulated and GTS_XID are used, even if the file is a baseline PDF and not PDF/VT. Inclusion of those keys in a PDF file that is being created for variable data printing likely increases the HVD scan speed.
HVD can cache any number of rasters per page in external mode, or one background in internal mode and build the final raster from these parts. In addition, it can cope with imposed flats where several images and text layers are placed on top of each other.
HVD internal mode (iHVD) is where the combination of cached and uncached elements to form the final page raster is performed within the RIP.
In HVD external mode (eHVD), cached and uncached elements are provided to the OEM’s own code outside the RIP, along with metadata defining how to reassemble these elements into final pages.
In eHVD, the elements cached can be position independent. This means that any single cached element can be used at multiple x ,y offsets on the page. Its use leads to increased efficiency, particularly for certain classes of VDP jobs such as those containing multiple coupons in lots of different permutations from page to page. This is enabled by default.
By design, iHVD is more restricted in which marks it can cache. Hence, eHVD and iHVD scans may identify different combinations of graphical elements for caching.
HVD external mode must be coupled with a plugin or raster backend that has a method of stitching together the resulting rasters. From version 14, a support library for these external raster stitching features is provided with the Harlequin Core SDK. For HMR, GGSL do not provide any support for raster stitching. If you do not have your own raster-stitching technology, you should use HVD internal mode instead.