A Full Plate

Offset plate suppliers stretch to manage conventional- and digital-world needs.

By Susan Friedman

Many offset plate suppliers are stretching to be in two places at once—edging conventional technologies up a notch while running like mad to win the digital marathon.

Convention rally

On the conventional side, Dwight Collier, national sales manager for pressroom products at Pitman Co., a distributor of printing consumables, equipment and services, sees "a conscious effort to continue to improve plate latitude in a variety of environments." Three areas of emphasis, he notes, are developing coating weights that are more resistant to abrasion, improving grain structures to achieve a more efficient water balance, and honing support chemistries.

In addition, Collier sees manufacturers looking at more stable aluminum materials that guard against tearing and cracking. Conventional plate latitude has already been boosted by the "wide industry sweep" from mechanical to electro-chemical plate graining, he says, which means only subtle processing adjustments are necessary to accommodate a new plate.

At Fujifilm, emphasis on conventional offset plate offerings continues "due to the projected slow implementation of CTP," states Product Manager Jim Crawford. Recent conventional plate improvements he cites include a matte surface that facilitates faster film drawdown to the plate surface in the vacuum frame. This increases platemaking productivity, while virtually eliminating halation. Environmentally safe aqueous developers are facilitating faster, cleaner processing, he adds.

Tom Saggiomo, chief marketing officer at Kodak Polychrome Graphics, also believes conventional plate needs can not be ignored, because "on a worldwide basis, even the most aggressive forecasts for computer-to-plate predict only 25 percent usage by 2002." At the same time, in his opinion, conventional innovations have been rather ho-hum. "There have been incremental improvements in conventional plates, but not a significant step-change," he comments.

Offset pressmakers, too, seem to have a short list of conventional developments. Randy Siver, product manager, Mitsubishi, says not much has changed since automated plate hanging improved plate mounting efficiency 10 years ago. From a press perspective, Siver sees the most potential in on-press direct-to-plate imaging (see sidebar page 36), particularly on smaller presses.

Computer-to-plate's climb

The migration to computer-to-plate (CTP) may be gradual, but it continues to gain momentum. A Pitman sales analysis illustrates digital's progress. In 1996, Collier reports digital technology represented 18 percent of Pitman's total sales. In 1997, this figure rose to 32 percent. And in the first quarter of 1998, digital product sales reached 38 percent.

The vigorous debate over visible light vs. thermal imaging continues, implying that neither technology will be fading from the marketplace anytime soon.

Fuji's Crawford believes thermal and visible light technologies have achieved equal market presence, with printers opting for one or the other based on previous vendor relationships, workflow needs, run length requirements and customer specifications. He says thermal plates have a slight advantage in run length and can be handled in yellow safe light conditions, while visible light plates offer the advantage of processing equipment with a smaller footprint. "Where it matters most," he emphasizes, "pressroom performance in such areas as roll-up and ink/water balance will be identical no matter which technology is selected."

"It's clear that both visible light and thermal processes will continue, because there is a need for both," comments Collier. "We have gotten very, very good at a conventional technology that can be exposed on a variety of imagers because of its broad sensitivity and imaging latitude. Digital plates are much less versatile; so far, each requires a dedicated processor and its own chemistry." Due to several recent manufacturer consolidations, Collier expects up to seven thermal technologies to ultimately take hold in the market, along with up to four each of photopolymer and silver halide alternatives.

Meanwhile, offset plate manufacturers have assumed a brisk pace of CTP product introductions aimed to build digital's appeal, even for those printers only willing to transition half-way.

The bimetal (copper electroplated to an aluminum base) plates offered by PDI simplify CTP implementation challenges by using the same chemistry and processors for both CTP and conventional applications. They can be sharpened digitally or chemically during processing so that digital files can be matched to conventional films, says Dwight Zilinskas, international sales/marketing manager. The plates do not require baking, which eliminates warping and cracking that may occur in other plates during the post-bake.

To address thermal technology weaknesses such as speed, handling and long processing trains, Agfa debuted its Thermostar plate line at IPEX. Product Manager Dave Furman says Thermostar plates can operate in true white-light environments without the need for a pre-bake. The photopolymer-based, positive-working plate provides run lengths up to 150,000 impressions without baking, and more than one million impressions with baking. It can be imaged in both internal and external drum platesetters.

By the end of 1998, Kodak Polychrome Graphics will introduce a no-pre-heat plate designed for customers who wish to avoid the space constraints caused by large baking ovens, says Saggiomo. In addition, the company showcased a new no-process plate at IPEX which eliminates pre-baking and chemical processing, and is designed primarily for short to medium runs.

CTP pricing issues have also prompted Kodak to release a companion product to its commercially available thermal printing plate, which is sensitive to both conventional UV light and thermal imaging. "The dilemma is that thermal dyes are more expensive," explains Saggiomo. "Some customers don't want to pay a premium to use this plate for analog applications." The new analog product is fundamentally the same plate as the CTP product without the thermal dye—a conventional printing plate that can be processed with the same chemistry as the thermal printing plate, allowing customers to use one plate system during the transition to digital plate making.

In a recent survey, Pitman asked customers to identify features that would constitute an ideal digital plate system. Their top seven answers, says Collier, were high resolution, pressroom acceptance, white light handling, commercial availability, versatile run length, cost-competitive pricing and process-free.

Cutting-edge costs

A price break for digital plates doesn't appear to be in sight—a situation that may be at the crux of conservative CTP implementation projections.

"Digital plate prices will remain high due to plate manufacturers' need to recover the R&D costs of new digital technologies," predicts Crawford. "Many printers still view these price points as a barrier to CTP, and continue to adopt full imposition imagesetting as an intermediate step," he says.

When choosing a digital technology, a simple price tag may not be the best indicator. "There are all kinds of rumors and innuendos that thermal is more expensive than visible light technology, but the prices are equal," states Saggiomo. "Thermal technology is priced commensurate with its value. It offers the most consistent, reliable, high-resolution CTP solution."

But perhaps price isn't the point of CTP, at least not for the moment. Zilinskas takes the investment angle with many of his customers at PDI. "With CTP, costs go up initially with the addition of a second workflow and digital staff," he points out. "Employees with digital prepress duties are often paid more than those on the conventional line, and can still come out more expensive when considered against the productivity cost-savings of an automated platesetter." He tries to steer customers away from "viewing the prepress department as a money-making venture. Instead, the focus should be on the pressroom cost-savings CTP enables."

New Angles in Direct-to-Plate

For package printers using older offset presses, the quickest route to computer-to-plate is likely through a platesetter, which necessitates manual removal and remounting of the plate after imaging. But those who have invested in newer presses, with quick-change features such as slide-out cassettes, can consider the efficiencies of direct-to-plate imaging.

Presstek has aligned with a number of press suppliers in recent years in order to bring direct-to-plate and computer-to-plate technologies to market. The company first teamed up with Heidelberg in 1991 to introduce thermal, no-process plate imaging done directly on Heidelberg's GTO press.

The outcome of Presstek's alliance with Nilpeter was recently on display at Labelexpo '98. The DI-3300 direct-to-plate offset imaging system, designed by Presstek for Nilpeter's M-3300 platform press, can image plates with 1270 dpi resolution in approximately five and a half minutes. The system can accommodate 15à to 30à repeats, at up to 175 line screens.

Nilpeter's DI-3300 represents "a step back" from all-out direct-to-plate, explains Presstek Product Marketing Manager Sandy Fuhs, filling an intermediate need for a stand-alone CTP device that provides nearly all the advantages of complete direct-to-plate. Cassettes containing the plate and blanket cylinders slide off Nilpeter's M-3300 and directly onto the imager. Once each plate is mounted, imaged, and slid back on to the press, it is immediately in register. The imaging system can also transfer ink key data directly to the press, Fuhs notes.

According to Nilpeter Digital Service Engineer Soren Ringbo, the DI-3300 uses 16 laser diodes to image Presstek PEARLwet plates for printing with dampeners, or PEARLdry plates for waterless printing. PEARLwet plates feature an aluminum base and a water-loving top layer which is heated and loosened during the imaging process. The released upper layer is then cleaned off with a solution that is 90 percent water, 10 percent Varn Total.

A Windows NT server functions as the RIP for images, while a mouse-driven Job Control menu can speed prep time by providing on-screen image verification, or a list of fingerprinted cassettes with pre-loaded settings.

The DI-3300 direct-to-plate offset imaging system can image plates with 1270 dpi resolution in approximately five and a half minutes.