Sizing Up Software
Functional specialties can help tailor prepress software to flexo, offset and other package printing processes.
By Susan Friedman
With commercial offset prepress needs nearly down pat, software suppliers' focus on package printing continues to intensify, with heavy emphasis on flexographic particularities.
"Because flexography and offset represent the biggest installed base of printing presses, they are the biggest arenas for more specialized prepress software," comments Alex Hamilton of Computers & Communications Consulting.
Ray Fennelly, applications manager at Contex, links flexo software growth to the process' steady transition from art to science.
Package printers seeking process-specific software won't always find "Just For Flexo" stamped on the box. Instead, suppliers generally specialize in a particular prepress function, such as trapping, explains Dave Burgess, product manager, package printing, at Creo Products. An open prepress workflow will enable a range of programs to handle problematic areas of a specific process, he says.
Software's functional specialties are also reorganizing prepress departments, separating staff members into distinct groups with responsibilities for critical color, package structure and plate assembly, says Susie Stitzel, product manager, Contex.
Specific Approaches
Prepress software which accurately prepares package or label files for a specific printing process can come in several different forms. First, a growing number of independently developed packaging software plug-ins are emerging to accompany off-the-shelf design programs for Macintosh and PC platforms such as QuarkXPress and Adobe Photoshop.
A lowly apprentice production's PlateMaker 2.0 plug-in for Photoshop allows any number of custom color, spot color or varnish plate separations to be produced from a Photoshop image, and saves the separations in one file. Without the plug-in, Photoshop limits users to CMYK or grayscale separations; special color effects must be created with manual stripping or a duplicate of the document. Product Manager Greg Hatem relates expanded custom and spot color capability is of particular benefit to flexo printing.
Other specialized software programs take over at the graphic preparation stage. With programs like these, says Stitzel, "We try to concentrate on aspects that Mac and PC can't handle, such as package trapping, nesting, and step-and-repeat."
"Step-and-repeat and distortion done in DTP software such as QuarkXPress or Illustrator are a significant source of prepress errors," affirms Pierre Ferland, international project manager, Alan Graphic Systems.
There are also complete software packages built from modules chosen based on application and process requirements. "Specialization is achieved by breaking down functional needs and purchasing modules accordingly," says Ian Hole, market manager for Barco Graphics. Barco offers linework and contone software as basic building blocks. These standard packages include specialized handling of vignettes, trapping and text. Functions such as stepping and inkswapping of process colors to special colors necessitate additional modules.
Functions to Look For
In a prepress workflow, package printers must control file incompatibilities that prevent software from understanding files created in an off-the-shelf design program. The Macintosh diecutting program Score, for example, does not accept Adobe Illustrator files, says Caitlin Lathan, sales manager, Kandu Software. This can be solved with a vector graphics translator such as Kandu's Cadmover, which imports the Illustrator file, scales, positions and saves it in a format Score can understand, then exports the file to Score exactly as it was created.
When it comes to preparing the package or label file for proof, film or plate output, "the biggest deal hands down is trapping of edges and corners," states Hamilton. One general capability to consider is what elements a program includes in trapping calculations. Contex software, for example, includes color tint, light to dark scales, ink opaqueness and order of ink laydown in its trapping assessments, says Fred Harrison, marketing manager.
Burgess says control over trap shape is particularly important to disguise the larger, easier-to-see traps used in flexo, while Ferland recommends trapping flexibility that doesn't lock flexo printers into trapping the lighter color into the darker color.
Flexo brings up fresh functional needs at several other process steps. For accurate step-and-repeat, prepress software must compensate for flexo's variable repeat lengths, and for flatbed or rotary diecutting operations. For correct calibration with an output device, the software's calibration capabilities should account for flexo dot gain tendencies. Screening software must generate flexo-specific angle sets and dot shapes.
PCC's FlexoCal achieves screening between 0 percent and 2 percent, says EVP Dennis Mehta. PCC's Hybrid Screening feature can transition a file from conventional to stochastic screening without creating a line in the contone image.
Petra Tant, product manager packaging and labels at Artwork Systems, recommends finding a fit by examining how the software is tuned for input and output devices. Artwork's ArtPro software handles multiple printing processes with tuning for direct-to-gravure, direct-to-plate and digital printing outputs.
RIPs (raster image processors), which interpret the prepared packaging file and feed the data to the output engine of choice, can also be tailored to a job. A flexo-specific RIP, developed by Alan Graphic Systems, applies step-and-repeat and distortion values on-the-fly to a one-up file by selecting the appropriate die and plate material from a database.
Timing is Everything (else)
Converters must also consider at what point in the workflow—during graphic preparation or RIPping—software performs desired functions.
Suppliers make many supporting arguments for the increased productivity made possible by applying functions such as trapping during the RIP. "When converters integrate prepress systems with separate components, certain functions such as Postscript trapping require separate operator actions, which will inhibit automation," explains Leigh Kimmelman, product manager, Output Imaging Systems, Scitex. "The vast majority of printers improve throughput by performing as many tasks as possible with full automation. The trade-off against automation is the possibility for customization of traps as they relate to individual color pairs. There are instances where interactive trapping is required and automation is not possible."
PCC Product Manager Robb Lutton recommends a workflow in which each element to be printed, such as a soup label in several flavor designs, is prepared and RIPped individually before step-and-repeat is applied. The individual labels can be edited and reRIPped much faster than one large multiple-image file, he says, and individual elements can be added or changed at the last minute.
