Editor’s note: In this article, newspaper techniques examines which computer-to-plate technology is best suited to a particular application. It has been edited by Newspapers & Technology.

Although computer-to-plate production is firmly embraced by Western European newspapers, the move to digital plate processing is still in full swing in other regions of the world.

Almost 95 percent of Western European papers now are produced with CTP; in Germany, for example, all but three or four of the 170 plants producing newspapers use CTP.

Agfa demonstrated its Advantage XM at Nexpo last year.
Photo: Agfa
 

Now, papers in the United States and Asia are following suit. In Japan, more CTP systems were installed between October 2004 and October 2005 than in all the years before, thanks to a pair of vendors offering systems capable of exposing the unique Japanese plate format.

Even as CTP penetration continues to grow, newspapers are still evaluating which technology - violet, thermal, computer-to-conventional plate - works best for them.

The first CTCP systems came on to the market some four to five years ago. Basysprint, for example, offered such a system that used a powerful UV lamp and a mirror to expose arrays on to conventional plates.

These systems are no longer offered for newspapers, but they are used in sheetfed production.

There are both technical and strategic reasons for this. The systems have simply not achieved the throughput required for larger or medium-sized newspapers, therefore making additional imaging systems necessary.

This made them unattractive for smaller newspapers, as the difference in price between CTP plates and conventional plates did not compensate for the higher imager costs.

Vendors, meantime, couldn’t cost-justify the investment needed to increase CTCP systems’ throughput, fearing they wouldn’t be able to raise prices high enough to offset the R&D necessary.

AlfaQuest, another major CTCP vendor, offered a UV laser-based system to image conventional plates. The system was seemingly too expensive to attract the business needed.

Violet silver - in or out?

Besides photopolymer technology, there is the possibility also to use violet lasers to image silver plates. This process continues to be in widespread use, for example, in Europe.

Indeed, in some applications it is still suitable to use silver plates. They are less sensitive to heat and humidity than photopolymer plates. That can be an advantage in some regions of the world. But even in India, it is now possible to guarantee a safe, air-conditioned plate transport.

Several plants are in the process of changing from silver to violet, or will do so in the near future. The main reasons are the expensive developer and that Agfa is the sole supplier, whereas with polymer plates there is now the choice of three suppliers: Agfa, Fuji and Kodak.

Violet photopolymer vs. thermal

Let’s take a closer look at the two strongest competitors in the race to reign supreme in CTP: violet photopolymer and thermal technology.

With thermal technology, it is important to make a distinction between the different market regions. The United States boasts a number of suppliers who are engaged in a fierce price war and whose repeated price reductions are bringing the price close to that of conventional plates.

(In Europe, by contrast, there is only one plate: Kodak’s Thermal News. Other vendors’ thermal plates are too costly for newspapers.)

For this reason, thermal was the clear U.S. favorite in recent years. But the violet industry is competing strongly on the U.S. market with increasingly low-cost imagers, some of which can be bought for less than $100,000. The price for violet plates has also dropped dramatically.

Personally, I see quality as the main advantage of thermal. The plate/imager combination supplies more stable results, something that many experts and users unfortunately overlook. The repeatability and exposure precision should not be ignored. The cost of quality control is certainly less than with violet systems. FM screens or finer screens are less of a problem with thermal than with violet. The process is simply more stable.

Furthermore, chemical consumption is relatively small and cleaning the processor not very work-intensive.

Advantages of violet photopolymer

The main advantage is the violet laser itself. Commercial DVD technology is driving the development of laser performance; consequently, lasers will continue to improve.

Today’s systems mostly work with 60-mW lasers and thus reach plate throughputs of more than 250 per hour. The near future will bring with it the introduction of 100-mW and 200-mW lasers. What’s more, the violet laser is slightly lower priced and simpler than the relatively expensive thermal laser.

Now that speed and throughput have hit acceptable levels, the next horizon is chemistry-free processing. Fuji has already announced the introduction of chemistry-free violet plates, although initially they will only be available for the commercial market.

Agfa demonstrated the possibility of chemistry-free imaging on a newspaper imager at Ipex ‘06 and Nexpo ‘06 and hopes to introduce these plates to the market by early 2008. It remains to be seen whether these plates will offer the same stability at the same price as today’s chemical plates.

In the meantime, production managers still must carefully investigate what they need before picking a CTP system. There is no standard solution, despite the fact that the choice is easier than it was four years ago.

Uwe Junglas is Ifra’s consulting director. He has followed the development of CTP for years.

This article was first published in newspaper techniques, the monthly magazine of Ifra. If you have any comments or questions about this article, please send them to ntreader@ifra.com. If you’re interested to learn more about the training and consulting services available to newspapers through Ifra’s joint venture with the Newspaper Association of America, please contact Technical Solutions LLC at info@technical-solutions.org.