February 28, 2024
The main difference between them is the way of exposure: Violet Plate uses a violet laser light source for exposure, and thermal sensitivity uses 830nm thermal laser exposure imaging. The accuracy of thermal imaging is higher than that of violet . In addition, the photosensitive plate (violet laser) needs to be operated under a safe light environment, and the storage environment of the plate has strict requirements. There are relatively few manufacturers producing violet plates.
Currently, there are only four brands of photosensitive violet CTP plates available on the market, but the prices are much higher than those of thermal plates. The storage conditions for thermal plates are relatively loose, and there are many brands to choose from in the market.
The medical film of the violet laser plate undergoes a chemical reaction when receiving the violet laser. In this way, the edge of the light spot will inevitably produce diffraction. The sharpness of the edge of the light spot is lower than that of the thermal plate. There is a limit to the acceptance of thermal energy by the exposure of the heat-sensitive plate. Threshold, if the thermal energy temperature is too low or too high, exposure will not occur. Exposure can only occur within the threshold. This imaging principle is that the edge of the light-receiving point of the plate becomes sharp, and the controllability of the dots is extremely strong.
Generally speaking, commercial printing plants (books, magazines, pictorials), packaging plants and other companies with high color quality requirements should use thermal printing. Violet CTP is suitable for high-speed production units that do not have high requirements for color quality, such as newspapers.
From the perspective of market share, more thermal sensors are used. With the development of technology, the speed of thermal CTP machines has also improved. For example, the Kodak Super Win 400 can already reach a production speed of 60 plates per hour.
IGS managing director Peter Flynn said the company's increased CTP success came about because violet plate options had dwindled, and existing violet CTP users were actively looking for an affordable upgrade path.
ECO3 (formerly Agfa Offset Solutions) is now the sole supplier of violet plates for the UK commercial printing market, with its N95-VCF product. It also supplies violet plates to the much larger newspaper market.
Kodak has a violet plate for commercial printing but it is not available in the UK.
Fujifilm phased out supply of its PRO-V violet plates for commercial print last year, but continues to supply violet plates for newspaper printing.
Flynn said: "What we can offer these customers is an upgrade path to an affordable refurbished thermal CTP. Moving from violet to a thermal CTP will allow the users to benefit from daylight operation and the ability to use direct-to-press plates. We also hold a large stock of spare parts to guarantee the longevity of their investment."
