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CTP plate issues: Pricing, new competition and technology

By Vincent Fournier

Not much has changed on the pricing front for plates used with computer-to-plate units: they are still more expensive than conventional ones.

If a newspaper that is already producing a high number of copies per film is considering a move to CTP, the decision is not based mainly on cost savings in the materials area, i.e. plates. It might be possible to save some money if there are only one or two copies per film, but the primary savings will not come from lower material costs.

It is interesting to take a closer look at the plate technologies on the market today, and to get a better idea of which CTP plate, in combination with the necessary imaging laser technology, works best for a publisher.

Because of the short lifetime of some laser heads, one might conclude that laser heads are consumables, too, and not a spare part, subject to a lot of wear and tear.

Plates: The war of nerves

Plates are one of the main material cost items for newspaper operations.

“Due to the small number of suppliers and a constantly increasing demand, the per-unit prices of the various CTP plates will not fall in the next years,” said Uwe Junglas, Ifra Research Manager. After 10 years of major investments in research and development, the plate producers logically aim to recuperate their losses through the pricing of plates.

As a result of the small number of specialized suppliers and a constantly increasing demand, the price per unit of the various plate models is not expected to drop in the next few years.
Photo courtesy of Ifra

The CTP boom at the end of 1998 was indeed a welcome relief for suppliers. The newspapers, which still sometimes suffer from supply problems, wait for changes that might not come quickly, but there are changes taking place in the market that will perhaps alter the situation in the foreseeable future (in the next two years). Silver and photopolymer CTP plates have one old competitor, the thermal plate, and one new competitor, the good “old” conventional plate used as a CTP plate. The recent takeover of Western Lithotech by the Italian Lastra company (one of the leading manufacturers of offset plates development products) can be expected to result in the development of new products and allow a better distribution in Europe. But aside from potential new products, let us take a closer look at the existing technologies.

1) Computer-to-conventional-plate: The good old computer-to-film and conventional plates, still used by more than 60 percent of European newspapers as well as the vast majority of U.S. titles, whose reticence towards CTP, in the opinion of Junglas, is due to “the tendency to think strictly about return on investment and that the conventional plate prices in the U.S. are lower than in Europe.”

Also, many U.S. newspapers still use the very inexpensive wipe-on plates (instead of the manufacturer pre-coating the plates, the printers in the U.S. will “wipe on” themselves, thus saving costs). Less expensive than CTP plates, the conventional plates are today experiencing a revival for use in short runs with the advent of CTcP systems. CTcP systems will give the greatest potential to save costs in the materials area. At the moment, the basysPrint UV Setter is emerging in the market and Esko-Graphics (formerly known as Barco and Purup-Eskofot) announced at Ipex plans to release its Dicon CTcP imager in 2003 as a newspaper imager.

2) Silver-based CTP plates, which account for about 40 percent of the European CTP plate market, used in the diffusion transfer process, which is the longest standing CTP technology, and that works in accordance with the following principle: a grained and anodized base is covered with a nucleation layer, then a silver halide layer; during development, the silver thiosulphates formed in the non-exposed areas scatter towards the nucleation layer to form lithographic silver that adheres strongly to the anode layer. After rinsing, a positive silver image appears on the plate.

This type of plate has the following advantages: high-quality resolution, no high-powered laser required (i.e. a longer lifetime of the laser, especially compared with, for example, photopolymer plates) and the plates do not react too strongly to humidity and temperature fluctuations. With regard to drawbacks, some major obstacles have been or will be eliminated.

In the past, the consumption of chemistry for non-violet silver plates was very high. It was higher than the consumption of the photopolymer plates. The prices of the two plate types were more or less the same, but the price for silver chemistry and silver waste recycling was more expensive.

New processing procedures are being tested, and Agfa hopes to lower the chemistry consumption costs close to the same level as that of the photopolymer plates. Agfa is still in a monopoly position in the newspaper market here. The only possible competitor, Mitsubishi, is not marketing its silver plate as a newspaper product.

For violet laser diodes there is again only one silver plate available for the newspaper industry today. Other plates have been announced, but these are not only silver plates.

So there is still the drawback of a single supplier situation.

The silver CTP plates designed especially for newspapers are the Agfa Lithostar Plus/Ultra (in green laser and violet laser versions) and with the above mentioned restrictions, Mitsubishi SDP Alpha R (also obtainable in a violet version).

3) Photopolymer CTP plates (about 40 to 50 percent of the European CTP market) work in accordance with the following principle: a layer of crosslinked polymer is applied to a grained and anodized aluminum base and covered with a protective coating to prevent oxidation. The light energy required for plate exposure is much greater than that required by the silver plates, which means that a much higher-powered laser is needed. This energy triggers crosslinking by activating the polymer, a reaction that can be accelerated by preheating. After the main exposure, an after-exposure guaranteeing total crosslinking or an after-heating are integrated into the development process. A conventional aqueous suspension developer then develops the plate.

The photopolymer plates are resilient, guarantee high quality printing and do not produce silver waste. Burning of the plates (Agfa N91) is possible to further increase their lengths of run. On the other hand, as we have seen, they require a higher laser power, compared with silver plates, and can require certain storage conditions in surroundings that are humid and subject to temperature fluctuations.

Available are the Western Lithotech LY-8, Agfa N91 and Fuji LP-NN2, the latter two being compatible (it is possible to develop Agfa N91 plates in Fuji’s chemistry). With some mechanical modifications, the existing processor can be used with the Western Lithotech LY-8.

4) Launched on the market 4 to 5 years ago, thermal plates have gained a good position in the newspaper CTP market. The plate is imaged by thermal energy and not light energy. The heat of the laser generates acid molecules that alter the solubility of the polymer layer. The plates react above a certain temperature, called the threshold value. When the threshold value temperature is reached, there is a reaction and the plate presents a latent image that must then be revealed by development and rinsing (damping).

The advantages of the thermal plates are two-fold, i.e. technical and ecological. The “binary” exposure limits the risks of over or underexposure and it is possible to work under yellow light. In another connection: the water-receptive plate substrate is comparable to that of an analogue plate: it is not essential to change the fountain solution or the ink quality on the presses.

“It is even possible,” according to Giuseppe Marchetti, member of the technical management of the newspaper division of the Italian Seregni printing company (which produces Il Corriere della Sera, Il Giornale, L’unitā, etc.), “to use these plates on conventional CTF lines, provided that they are developed by a suitable processor.”

As a result of stricter regulations (European directives 29.50 and 24.50), environmental impact has become an important consideration and thermal plates have a trump in the hand in this respect. They contain no silver and, according to the manufacturers, contain fewer chemical products. Kodak Polychrome Graphics is also promoting an anti-accumulation process that prevents accumulation of sediment in the developer.

Regarding drawbacks, it must be admitted that these plates require infrared lasers (that in many cases have a fragile head) that generate more energy than lasers that work in the visible spectrum. There are two types of imagers, Kodak Polychrome Graphics’ Newsetter and Creo’s Trendsetter News.

“The various CTP plate technologies are almost identical in relation to price,” Junglas confirmed. “The difference is mainly in the cost of the chemicals used. In this respect, the thermal technique appears to have an advantage, but the suppliers of silver and photopolymer plates have made a great deal of progress in reducing their waste volumes.”


The emergence of the violet laser

Even if a laser cannot be judged as a “real” consumable, it makes sense to calculate lasers as a consumable. Because of its short lifetime (1-2 years are reported by users for the FD-Nd-YAG) and high price tag, it makes sense to calculate the laser into a consumable category. Various laser technologies can be used in CTP systems, depending on the types of plates used.

To begin with, there are the argon-ion (Ar-Ion) lasers, activated by exciting gas atoms. These are very stable, high-powered lasers (1 to 10 watts) that work in the blue-green emission wavelength range between 452 and 514 nanometers, the two main wavelengths being 488 and 514 nm. Because of its relatively short lifespan (4,000-5,000 hours, or only six to seven months in production conditions) this laser is now nearly non-existent in newspaper imagers.

Among the “solid” lasers, a distinction should be made between the Nd-YAG lasers and their FD-Nd-YAG cousins (whose frequency has been doubled by a special harmonics generation technology). In both cases, the laser source comprises a yttrium and aluminum garnet (YAG) doped in neodymium. The Nd-YAG are capable of generating high levels of power up to 100 watts in continuous waves at a wavelength of 1,064 nanometers, but cooling systems must be adapted to suit them. The power of the FD-Nd-YAG varies between 100 and 400 milliwatts. These are extremely stable models offering a useful life exceeding 10,000 hours, but they are expensive. The FD-Nd-YAG is being used in most of CTP imagers (for example, Agfa Polaris, Krause LS Jet, Western Lithotech DiamondSetter, Esko-Graphics DMX, etc.)

Finally, the laser diodes consist of two layers of semi-conductor materials in a sandwich arrangement, to which the laser module manufacturers (such as Coherent, Power Technology, Spectra Physics or Toptica) add optical and electronic enhancements. Much less expensive than the FD-Nd-YAG, these laser diodes cover a large emission bandwidth. The red laser diodes (RLD, emission spectrum focused at 670 nanometers) have a useful life of 2-3 years. Thermal CTP systems mostly use “near infrared” laser diodes (wavelength 830 nm, power approximately 10 Mw) that have a useful life of 2-3 years.

According to Kodak Polychrome Graphics, thermal technology accounted for two-thirds of CTP system sales in 2001.
Photo courtesy of Ifra

As the most recent arrivals on the newspaper market (though these have been in use for several years already in the reading heads of DVD systems), violet laser diodes work with much shorter emission wavelengths (between 390 and 430 nm).

“This has two decisive advantages,” explains Gregory Flinn, from the R&D division of Toptica Photonics, a company that specializes in supplying laser modules for scientific research or DVD systems but that has recently made tentative moves into the CTP newspaper market.

“The laser heats up very quickly (at most several minutes as opposed to half an hour for a FD-Nd-YAG laser) and does not reach too high temperatures: therefore it is possible to increase or reduce the laser power outside of the actual exposure times,” Flinn says.

This increases the useful life of the laser, comparable in absolute terms to that of a FD-Nd-YAG (more than 10,000 hours). “Based on 16 working hours daily,” says Flinn, “a FD-Nd-YAG will be ‘burned out’ after 625 working days, whereas the violet laser diode can attain 1280 working days.”

Carl Mosby, head of the CTP project of the Yorkshire Post in Leeds, United Kingdom (a member of the Johnston group, formerly RIM), which became one of the first newspapers to switch to this new technology, confirms the reliability of his equipment: “We have not had the slightest problem since the installation of our Monotype system in January 2001. The violet laser is reliable, highly productive and highly competitive: we have calculated that it cost up to 1.5 euro less per square meter of plate than the green FD-Nd-YAG.”

It is interesting to note that, after the experience of the Yorkshire Post the Johnston group decided to acquire six Polaris Violet imagesetters.


CTcP makes its debut in Germany

It is the first CTcP installation worldwide. With effect from November 2001, the Von Stern’sche printing company in Lüneburg, North Germany, has been testing the basysPrint UV Setter 57-Z imagesetter that works with conventional plates (Agfa N550) and an ultraviolet light source. This imagesetter, which is equipped with two exposure heads, can produce 70 plates per hour with a resolution of 900 dots per inch. The Overlay Generator software automatically carries out calibration of the imagesetter.

The most interesting aspect of this system is the low cost of the conventional plates, nearly two times less expensive than the various CTP plates.

“The savings achieved in six months totaled 35,000 euros,” said company director Andreas Jörss, “To which must be added the savings for plate development, the cost of which is estimated at 0.05 euro for a conventional plate as opposed to 0.14 euro for a silver plate.”

The only drawbacks: the UV lamps of the laserheads must be replaced every 600 hours. In terms of price, the basysPrint system is a little more expensive than an ultraviolet CTP system but “the return on investment is very fast due to the cost savings obtained,” according to Andreas Jörss.