The type of plate you choose, can impact your bottom-line.

The concept of Computer-to-Plate (CTP) technology is relatively easy  for those in the printing industry to understand, but the numerous nuances and wide variety of manufacturers often make it difficult for business owners and decision-makers to choose the best solution for their specific business needs.

One such distinction is the type of printing plate —the tool which transfers images onto a certain type of material to create the final product — that will meet your expectations.

Thermal plates are the most common among pre-press and printing operations. However,  like most solutions,  each technology — thermal, photopolymer and silver-halogen plates — has its pros and cons.

Here’s a look at those differences.

Photopolymer Plates

Photopolymer plates have experienced many changes over the years.

Louis Minsk, an employee of Eastman Kodak, patented the 1^st  synthetic photopolymer plate in 1952. Time, Inc. introduced the 1^st  photopolymer-based letterpress plate in 1957 for printing magazines Jump to 2002 when DuPont’s Cyrel Fast technology entered the market, eliminating the need  for solvents in plate processing and melting unexposed photopolymers. Photopolymer plates differ from other technologies by applying a light-sensitive coating to the surface of an aluminum plate, exposing it to light, causing the coating to harden in image areas and remain soluble in non-image areas.

Advantages

• Coatings provide more durable and abrasion-resistant image areas
• Produce longer print runs up to 250,000 impressions
• Have been known to print runs of more than 1,000,000 impressions
• Dye-sensitized photopolymers can be etched by lasers
• Requires more energy for exposure

Disadvantages

• Requires a chemical treatment after exposure to remove the coating in non-image areas
• Cannot print as high of a resolution as silver-halide plates

Silver-halogen Plates

Also referred to as  silver-halide (silver salt) plates and silver-based violet plates, silver-halogen plates are used for offset printing and use a film- or metal-based plate coated with a silver-halide emulsion, similar to processing photo film. Silver halide is one of the chemical compounds which can form between the silver and halogen elements. This technology varies in that it transfers the image directly to the surface of the plate.

However, silver-halogen plates are less widely accepted in the industry and experts predict they will eventually become obsolete because they harm the environment more than other technologies. As a result, silver-halogen plates are being replaced with photopolymer plates (described above).

Advantages

• Silver-halide plates can be etched using photographic negatives
• Requires low laser energy for exposure
• Lasts up to approximately 350,000 runs
• Can print up to 450 LPI
• The silver provides a faster emulsion and require less energy for exposures

Disadvantages

• High sensitivity to blue light so developing and storing plates require a darkroom with a yellow-filtered light
• Processing chemicals contain heavy metals — in particular, silver — which pollute the environment
• The liquid waste produced contains metallic silver and classifies concentrations above 5 parts per million (PPM) as hazardous waste
• Discharging any silver into a sewer is also regulated and must be treated a specific way, or sent to a special treatment plant
• Relies on photosensitive materials which are more expensive than other technologies
• Is not known for its durability
• Requires specific ink
• Unexpected failure during any step of the process will damage plates

Making the Choice

There are different ways printers can determine what plates the need for specific platesetters. The first step is to test the plates you may be considering on your platesetter and presses. Of course, this means purchasing various types of plates. Once you’ve determined a plate works, you need to consider direct cost — including plates and processing expenses — and indirect costs, such as purchasing a processing, or baking unit.

True in any industry, it pays to hire an expert for advice and equipment warranties. Platesetters.com is one such expert and has earned a  global reputation as the most dependable source for reconditioned prepress CTP equipment, parts and service. For a complimentary consultation about your imagesetters’ plate needs, call Platesetters.com at 888-380-7483.