Practical Application Analysis of CTP Plate (I)

Compared with traditional CTF technology, CTP technology undoubtedly has greater advantages. CTP brings not only technological process and time savings, but also a technical revolution in the printing industry, mainly in the following aspects:

Changes in the production process: not only the film has been saved, the entire process has also changed.

Changes in production quality and quality control standards: The quality of the CTP technology itself is rising; the integration brought by the CTP process reduces and unifies the process control process and standardizes and unifies quality control standards.

Changes in production operations and production costs: In the actual application of CTP, once it is used improperly, the advantages of CTP are not obvious. In the process of developing and marketing Huaguang thermal CTP plate material and providing market technical services, the traveler has accumulated certain experience on how to correctly use CTP. The following questions on the use of the use of cases to be analyzed, and on how to correctly use the CTP plate provides some views for reference.

I. Misunderstandings and Analysis of Current CTP Applications
1. CTF standard can be used for CTP output
In actual production, whether it is CTF out of film or CTP out of printing plate, the file has a curve correction process when performing RIP, which is commonly referred to as linearization. Because the use of traditional photographic film printing, it is impossible to eliminate light refraction, transmissive color and reflection and other factors, there will inevitably exist dot enlargement (Editor's Note: This refers to the use of positive version of the printing version, the positive version is the contrary). Taking a 50% dot as an example, if you want to get a 50% dot on the plate, the corresponding 50% dot on the film should actually be less than 50%. The plate obtained through CTP direct printing directly reflects the electrons. The dot of the original, there is no intermediate transfer process. Obviously, the linear curves obtained from CTF and CTP are the same. If an image file produced according to the CTF standard is used for CTP output without any correction, it will result in larger dot gain value, dark tone and blur. The tone range is reduced.

2. The linearity of the plate making machine is certain and can output various CTP plates
At present, the thermal CTP plate has been domesticated. Some imported versions previously used by CTP users now want to switch to domestic versions. why? This is because the factory had a commissioning process when it installed the platesetter. Including the focal length value according to the thickness of the media, laser power and linear adjustment based on sensitivity, and finally a set of the best data to work. Because any two different media have different properties, the focal length, laser power, and adjusted linearity may all be different, and a new set of working data must be re-determined so that the best imaging performance of the publication can be achieved.

3. Higher cost of using CTP
The price of CTP plate and PS plate is relatively high. In fact, this is only a superficial phenomenon. By comparison we can see:

Traditional Publishing: film + punch + imposition + print + punch
CTP Publishing: Publishing + Editing
The use of the CTP version has reduced the three work steps and saved three staffing costs. And time has been reduced by several times, and the work cycle has been accelerated. It has been able to do the work of the previous days. Excellent image matching and registration, stable ink balance, greatly increase the yield of printed products and reduce costs. The high-resistance force reduces the chance of making up the plate and reduces the cost. CTP plates are used on web machines and the cost reduction is very obvious.

With regard to the CTP version of the Indian Force, various users have different opinions. This is mainly related to platemaking conditions and printing conditions. In order to maximize the resistance to printing, we give you some suggestions:

(1) Under the premise of ensuring the quality, use the minimum pressure (including each roller, ink roller, water roller, etc.) to reduce the friction on the layout.

(2) Ensure that the surface linear velocity of each roller and ink roller is equal as much as possible to reduce plate wear caused by slippage.

(3) Use the least dampening solution and strictly monitor its pH value under the principle that the plate cannot be dirty.

(4) Control the thickness of the ink layer to prevent imprint spreading.

(5) Reasonable use of driers to prevent premature drying of the printed surface.

5. No need for high resolution in actual printing
The biggest advantage of the CTP plate compared to the conventional PS plate is that the cable is higher and the dots are more delicate. With the current commercial printing, the quality requirements for printed materials are increasing. The use of CTP plates is an inevitable choice. Normally, the CTP plate can be clear and full from 1% to 99% of the dots in the correct exposure and development conditions. This shows that the CTP version has very good imaging capabilities. The quality of the printing plate can affect the quality of the printing product, but it is only one of the factors. To get a good print not only depends on the quality of the printing plate, but also requires the printing press, ink, paper and printing conditions to jointly decide. Usually Heidelberg four-color machine, good coated paper can only print 2% to 98% of the outlets, generally offset paper in the 5% to 95%, and newsprint in the 10% to 92%. In this case, it is impossible to distribute the image hierarchy 1% to 99%. Each printing plant should decide on the rational distribution of the dark tone before the printing plate according to its own printing conditions, that is, the level adjustment. In this way, the phenomenon of netting, shadowing, and paste will never appear.

(to be continued)