CTP FIELD REPORTS -- Set to Compete
Half of the printer's work is magazines, some with fairly long run lengths, and the other half is catalogs, some with very high page counts, the prepress exec says. In addition to the MAN Roland, the shop currently runs two other web presses—a 50˝ Heidelberg and 16-page Mitsubishi. It replaced two half-size web presses over the course of the four years, Long notes. "At one point, though, we were feeding four presses with four different plate sizes from the same platesetter."
Run lengths factor into the company's choice of plates. "We use Spectratech thermal plates because they are a little more durable than some of the newer no-bake plates, which can have issues with scratching," Long asserts.
The decision to adopt CTP in a VLF format came down to a fairly straightforward mathematical ROI calculation, but it also provided some added benefits. Tight registration is challenging to maintain with conventional prepress on a large format, he explains.
"When you are stripping film to big Mylar sheets, the thermal expansion from just a few degrees in temperature change makes a big difference in how far out of register the edges of the film will be. One of the reasons we chose the Creo platesetter was because it offers automatic thermal expansion compensation," the prepress exec notes.
"We've also used another option, called Web Growth Compenstion, that to my knowledge is only available through Creo. On a web press, the paper picks up moisture as it goes through each unit and starts to expand. On the larger press sizes, the web can expand by as much as two or three rows of printing dots. As a result, all of the colors will be out of register. We can calculate the rate of expansion for a given paper and web width, and the platesetter will automatically compensate for that expansion when imaging the plates," Long points out.