What Is a Computer-to-Plate Process? • TechRT

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Most industries have experienced tremendous technological advancement, and the printing world is no different. Ever since the discovery of the Printing Press, the industry has made efforts to improve efficiency, which has led to the latest development, i.e., computer-to-plate (CTP) technology.

Printing Press

Due to its contemporary nature, some users have hesitated to jump on CTP. However, you should know that this imaging technology is fairly straightforward and efficient. It is cost-effective and time-saving, mainly because, unlike the computer-to-film (CTF) process, CTP has a shorter process.

Below, we’ll dive into the different CTP technologies, their benefits, and what to consider when selecting a CTP tech for your business.

Understanding CTP

CTP printing is a streamlined process that directly produces a finalized file to a plate from a computer. The CTP plates consist of different materials such as polyester. And, immediately after imaging is complete, this technology ensures the final image is usable in press. CTP differs from CTF; traditionally, you would have to wait for the file to reach the film processor. Afterward, the file would go to the plates before finally reaching the press.

CTP eliminates this extra process while mitigating the health and environmental risks associated with the chemicals used in CTF print production. Additionally, it lowers costs since you no longer need as much film as you did before. One more advantage, CTP is much faster, meaning less time spent printing which translates to more savings on supplies, equipment, and labor.

There are two primary ways to differentiate the existing CTP methods:

  • Construction type: Three imagesetters exist external drum, internal drum, and flat-bed types.
  • Light sources: The primary types are laser diodes and ultra-violet lamps. The former’s energy and wavelength vary based on the plate type. Also, laser diodes are popular options for newspaper printing.
Printing Equipment

Types of CTP Technologies

While there are several CTP technologies in the market, the main ones are:

  • Thermal
  • Violet
  • Poly Plate
  • Inkjet

Thermal and violet CTP utilize laser diodes as their light source to convey the image to the plate. The primary differences between these two CTP technologies are their wavelength and laser color

First, the violet CTP technology has fewer colors than thermal CTP systems and, as a result, is more affordable. A glance at both machines will show that thermal machines create better quality products. Additionally, it produces over 300lpi line screens. In comparison, a violet CTP can only produce up to 300lpi.

These low laser numbers make violet machines light sensitive and, as a result, will need a safelight area to operate optimally (usually yellow). Alternatively, you may use the auto-load option. On the other hand, thermal machines do not require special light conditions and can work under average daylight.

The violet machine shines in terms of printing speed. As for the press, this machine type will slightly exceed 100,000 impressions. Thermal machines operate at an increased rate allowing anywhere between 200,000 and 400,000 impressions. What’s more, if you wish to increase the number of impressions to, let’s say, a million, you could bake the thermal plate.

Maintenance and Performance

Now that you clearly know each machine’s capabilities, you are probably asking, what about maintenance? As you would expect, it is much cheaper to maintain a violet platesetter than a thermal one.

Inkjet and poly plate machines are also popular image printing options. Due to their low purchase and maintenance requirements, inkjet computer-to-plate systems are the more affordable option. 

Similar to your desktop, these machines utilize inkjet technology to create plates. Additionally, inkjet systems have a parallel run length to violet machines, with at least 50,000 impressions.

Additionally, inkjet CTPs, like thermal machines, are usable under normal daylight conditions.

Poly plate CTP uses laser diodes to transmit images to the plates. A unique property of this system is the use of red lasers found in imagesetters. As a result, this system has both CTP and CTF capabilities.

Therefore, if you acquire a poly plate system, this machine will utilize light-sensitive plates, and after an integrated punch, the output can proceed to the press.

The printing speed for inkjets and poly plates varies. If you compare the other two systems mentioned earlier, you’ll realize that all four can hack up to 120 plates per hour. The critical determinants for speed include the plate type, manufacturer, and light source strength.

To that end, what CTP should you acquire for your business? The answer will depend on your printing needs, business type, and budget. Once you evaluate these three factors, an additional consideration to make is the maintenance cost. How sustainable is your choice of CTP? To help you answer this question, we recommend identifying the must-have supplies and the CTP laser strength.

Additionally, you may have to perform test runs to determine which system suits your printing needs.


CTP is a game changer for businesses needing fast, cost-effective, and efficient image technology. Several options exist. Therefore, it helps to consider whether a specific system is within your budget and appropriate for your business. Ultimately, regardless of whichever CTP you select, it will increase your bottom line.

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