Frequently Asked Questions

What to consider when shopping for a computer-to-plate system.

Length of runs

• less than or more than 100,000
• how many plates per day

Size of press being used

• proprietary could be an issue (i.e.Presstek)

Target market quality required

• hi-end
• average day-to-day
• commercial printer

Environmental issues:

• restrictions
• local or state EPA

Budget

• How much?

Plates

• thermal – more available, quality is better
• violet – good for moderate jobs

Thermal vs. Violet

1. 1. Advantages (pros) and disadvantages (cons) of thermal vs. violet equipment.
   
   Thermal:
   • Pro - Plates are available from a wide variety of manufacturers.
   • Pro – Chemical-free and true processless plates are available, so you can avoid hazardous chemistry, or a finishing unit/processor entirely, depending on the plate type.
   • Pro - Highest quality if you need to do lenticular or other very specialized printing.
   • Pro - Plates are not light sensitive, so plates can be handled and imaged in a daylight environment.
   • Con - Equipment tends to be more expensive than the systems using violet lasers.
   • Con - Laser cost is higher than systems using violet lasers.
   Violet:
   • Pro - Equipment tends to cost less than the thermal systems.
   • Pro - Lasers tend to be less expensive than those in thermal systems.
   • Pro - Plates are available from a wide variety of manufacturers (for photopolymer plates).
   • Pro - Machines tend to be smaller in size than comparable thermal devices.
   • Con - Plates are light sensitive and require a safelight environment or a fully automatic system in order to avoid accidental exposure of the plates.
     • For the fully automated system – the system will automatically feed the plate from a cassette into the platesetter, and then from the platesetter into the online processor. Since all transport of the plate is done within the equipment, safelights are not required.
     • For non-fully automated systems, yellow safelights are required. Safelight sleeves for light fixtures in the room will have to be purchased. These sleeves block out rays that can expose the plates as they are loaded into the platesetter and carried from the platesetter to the processor.
     • If the equipment is going to be used in an office environment, safelights aren't really practical.
   • Con - There are no true "Processless" plates that work with violet lasers. Agfa and Fuji have introduced chemistry-free plates, but they do require a finishing unit to prepare them for the press. A pre-heat section is required on the finishing unit, so these are not inexpensive machines.
2. 2. There are 2 main types of violet plates - plates with a silver-based emulsion, and plates with a photopolymer-based emulsion. Here are some points to consider on these technologies/plates:
   
   Silver:
   • There is only one manufacturer of these plates – and that is Agfa.
   • These plates require very little laser power to expose, so they can be imaged with all violet lasers on the market, including the original 5mW lasers that are found predominately in Agfa Palladios and Galileos.
   • Other machines with more powerful lasers (such as 30mW or 60mW) can image these plates, but a filter is required to reduce the amount of energy that hits the plate.
   • The developing process on the silver plates is quite dirty, so routine maintenance of the plate processor is critical for system performance and plate quality.
   • Equipment that works with these plates is the least expensive CTP equipment on the used market. However, buyers need to keep in mind that there is only one plate manufacturer, and as such, there is not the flexibility in acquiring plates that you have with plates for photopolymer or thermal systems.
   Photopolymer:
   • There are a variety of manufacturers of these plates, including Agfa, Fuji, Kodak, and others.
   • These plates require more energy to expose than silver plates. A 30mW laser or higher is required.
   • These plates require a different processor than the silver plates for developing. These plates require a preheat unit on the processor, and these processors are in short supply on the used market, and tend to be the most expensive of all the plate processors.
3. 3. There are many factors to keep in mind in determining the system that is best for you. Price is not the only consideration. In addition to price, these are other issues to consider:
   • Plate availability and cost in your region. Are plates regularly available at a reasonable price?
   • Available service for installation and ongoing support. Are there technicians in your region who can install the equipment that you choose? CTP machines are most definitely not self-installable - an experienced technician is required.
   • Planned location of the equipment. Can you accommodate the size of the equipment, and are safelights feasible if it is a violet system?
   • With a silver system, does the low acquisition cost of the equipment justify taking the risk of plate price increases or discontinuation?
   • With all equipment, it is advisable to determine the approximate laser use whenever possible and replacement cost, since it is a significant issue on many of these machines, especially thermal systems.