Computer to Plate Systems
- Involves direct exposure of printing plates by computer controlled laser, laser diode or LED.
- These are similar to imagesetters and many units (platesetters) can also image film.
- This makes the transition from film based workflow to Computer to plate (CtP).
- Instead of buying a new imagesetter, the printer buys a platesetter, but workflow transition can be eased.
- Prices now vary between $10,000 and $700,000 depending upon whether polyester or metal plates are imaged.
- This technology has been around for longer than we might think.
- Some phototypesetters were capable of monochrome plate exposure in the 1970s.
- Their acceptance was limited by ability to handle assembly and management of digital pages.
- It took developments of microcomputers and software to make them productive.
- Now have systems for the preparation of pages and impositions with usable picture and graphic handling subsystems.
- The issue of digital proofing remains, but proofing systems are improving everyday.
- This is a perception issue, rather than a technical one, since printers and their customers are accustomed to proofs made from the same films as the plates.
- Many CtP products available from many vendors (Barco Graphics, Cortron, Creo, Gerber, Printware, Linotype-Hell (now merged with Heidelberg), Agfa, Presstek, Scitex, etc).
- These are all vendors of CtP for offset, but Dupont is involved with systems for both flexo and offset.
- Most systems are driven by PostScript RIPs.
- Imposition programs such as Impostrip or Preps are required because manual stripping is not an option with CtP.
- Most CtP systems cannot handle advertising submitted only as film.
- The Cortron Digital PageStripper is an exception, in that it can automatically handle both digital files and images recorded on film.
- The DDAP (Digital Distribution of Advertising for Publications) Association has established a standard for distributing ads in digital form.
- The adoption of CtP systems has been driven by need to
improve productivity and reduce costs.
- As of Dec., 1996, fewer than 400 CtP systems were in operation worldwide (~200 in US.)
- This grew to over 800 in 1997. It is projected to grow to 5-7000 by 2000.
- Before adopting, companies have to determine how production flow systems, proofing and archiving can gain full benefit from these technologies.
- CtP is currently used for books and financials, magazines and catalogs.
- Improved environmental impact because of elimination of film and associated chemistry.
- There are many types of plates.
- Platesetters cannot image conventional plates because light sources don’t match UV of conventional platemakers.
- Types include Silver Diffusion Plates, Electrophotographic Plates, Photopolymer Plates, Inkjet Plates, Thermal plates or combinations of these.
- Light sources may be Argon ion laser (488nm), Frequency doubled YAG laser (532 nm), He/Ne laser (633nm), Red LED/Laser Diode (670,680nm), IR Laser Diode (760, 780nm) and IR laser (thermal 830+nm).
- Plate exposure systems may be flatbed, curved bed, internal drum or external drum.
- Platesetters vary from 16x23" to very large format of 66x82".
- Platesetters may be installed in the prepress area, in the plateroom or in the pressroom.
- GATF has developed a Digital Plate Control Target for Quality Control.
