Thermal or Violet Plate – Which is Better? Part 2

What about run length: Thermal plates offer longer run lengths, but to achieve this, they must be baked. Unbaked run lengths can be anywhere from 100,000-350,000, but when baked, thermal plates can exceed 1 million impressions. Processless thermal plates can give run lengths of 100,000 impressions. Violet plate run length varies among manufacturers, from 100,000 to 250,000. Violet plates can also be baked to yield even longer run lengths .

What about plate cost. The most expensive plates are processless thermal plates. We are finding that cost per square foot on plates that require chemistry are about the same with both technologies. You will however find that your chemistry cost may be a little more with violet.

Environmental Concerns: Silver-based violet plates are the most harmful to the environment but that technology has become almost obsolete, having been replaced with photopolymer violet plates. Photopolymer violet plates do not have the hazardous issues associated with silver based violet, but they do require chemical processing. Thermal plates are silver-free, but many still require chemical processing. However, there are also processless thermal plates available which eliminate the need for chemicals entirely, thereby providing the least environmental impact.

Maintenance Costs: Maintenance cost for violet platesetters will be significantly lower than thermal over the life of the equipment. In violet platesetters, there is only one laser diode to replace. In some thermal platesetters, there are multiple diodes that may at some point necessitate replacement. In other thermal platesetters there are multiple diodes that cannot be replaced individually as they are enclosed in a single very costly head. Not only are lasers less expensive to replace, they are also longer lived in violet machines. Another cost associated with thermal is the replacement of the plate clamps which are not used on violet platesetters. The maintenance cost on a violet plate processor can be more costly than on a thermal plate processor. Violet chemistry usually gets dirtier than thermal chemistry due to the coating on the violet plates, this can at times cause problems with the processor. This is however more of an issue with silver violet than with photopolymer violet.

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