First, the importance of film

Film plays a role in the printing and is an indispensable part of printing. We all know that the printing process is: original → plate making → output film → proofing → printing → post processing → finished product. Although the digital direct-to-plate technology CTP is developing very rapidly, it will take a while to popularize applications. The film in the traditional printing process is still one of the key links of printing. Without film, it cannot be printed and cannot be printed.

Second, check the purpose of the film

The earliest printing film was made by photolithography. The level of human factors and technology have a great influence on the quality of the film. Now, the printing film is generally a photo-distribution machine that interprets the prepared document as a digital image by using rip. , and then output the result of the layout is completed to the film. The film quality influencing factors include the perfection level of the software rip, the working experience of the production staff, and the working experience of the distribution personnel. The degree of understanding of the use of the software by the production staff and the release personnel determines whether the output film can be normally printed on the machine. The error rate is very high, so checking the film is necessary for each printing company and prepress company. The purpose of checking the film is to eliminate various unfavorable factors in the printing process or to avoid some printing process errors that may occur.

Third, check the tools of the film

Magnifier, scale, standard chromatogram, oil pen, densitometer, dot angle ruler

Fourth, check the film steps

1. After obtaining the film, firstly confirm whether the film quantity is consistent with the requirements of the use. Generally, it includes a monochrome film, a four-color film, a spot color film, and a film with a positive back cover.

2. Under the premise of determining the appropriate number of films. Check the film fit. In general, one sheet with a large area of ​​color is used as a reference on the platen, and the other three sheets of film are fitted. Under the normal thickness of the fitting line, no more than half line error is allowed. Text, lines, and image edges cannot be ghosted.

3. Next divide each film color. Some films have a color standard CMYK, so don't talk about it. Some films do not have a color mark, which can be identified by contrasting the color blocks of the film against the characteristic color blocks on the color manuscript and marked with an oil-based pen. If the film in question needs to be reissued, it should be noted that the first time and the second time should be marked separately.

4. Check the film size. According to the worksheet, check if the film size is the same as the requirement. When outputting the film, add all the centerline, sleeveline and cutting line. If there are proofs, do a good job of proofs of the finished product. If there are no proofs, check the dimensions as required by the size of the finished product. One item per item must be checked. If it is a bag, envelope or kit, and other informal size requirements, but also carefully check whether the sticky mouth, folded mouth, bottom of the box, bleeding, leaving enough white edge and so on. Finally, check whether the film size plus the size of the mouthpiece can be printed normally. (Large-version version adds 13mm to both sides, and if the paper does not allow, it must be printed in two versions).

5. Checking the imposition method is also very important. Imposition methods are generally self-reviewed, large-version version and large version. What kind of layout to fight depends on the specific circumstances, since the version and large version should be symmetrical with the middle line, it is very important to check whether the distance from the center line to both sides is equal. The imposition direction should be relatively symmetric, and the error of the large version of the front cover should be within 1 l, and the corresponding lines can all be matched. Also note that some work staples that require posterior binding or folding must be correctly folded.

6. After the imposition is correct, check the layout and text. Check whether the customer's place of change is correct, and then check whether the layout and content of the customer are consistent with the manuscript. Properly proofread and proofread the wrong mistake. The position of the mosaic must be accurate and the content can be connected.

7. If there is only plastic cloth with no proof on the color spray, it is necessary to check whether the color of each color version of the four-color film is consistent with the color separation of the color draft, and the color on the color draft should correspond to the corresponding film.

8. If it is a re-issued or modified layout, the application of the new film and the old film color version one-to-one correspondence check, the change has changed or the color density or the number of points in the network has changed, the old and new films are marked with oil pens.

9. Carefully inspect the flat screens, transition nets, and whether there are scratches, dirty spots, false light spots, laser lines, creases, and noise on the picture, and whether the transition is smooth.

10. Experience If you can not determine the density of the film can meet the printing needs, use the density meter to detect the film, according to the film platoon 3.4 above, the electrical fragmentation 3.8 or more.

11. If there are no traces of profiling on the proof or proofing, check the angle of the screen. Under normal circumstances, the angle of the screen is 0°, 15°, 45°, and 75°. If there is a uniform angle between the two color versions of the network cable, a moire must occur and the cable angle must be changed.

12. If you feel that the film network cable is rough or the proofing network is large, you should check if the number of sender lines meets the needs of the job. Offset printing is generally 130l, newsprint is generally 100l, coated paper is generally 175l, and high-grade printing is generally 200l.

13. After the entire film is inspected, it is best to use some eye-catching pens to draw out changes in some places. Explicitly indicate where to change. If you can't change it by hand, please re-issue the film. Otherwise, it takes a long time to associate with the sun, the printing plate is difficult, it is easy to make mistakes, and the customer's requirements are high. It may not be possible.

14. The excess corner lines within the finished product line must be removed.

15. Some of the above checks may have been avoided in the production process, some may not be used, and are too cumbersome. I hope to use my knowledge and experience in the inspection to select uncertain and unsure ones, saving inspection time. ,Improve efficiency.

16. Under normal circumstances require the customer to proof, after proofing out, you can find many problems and solve many problems, and then combine the film can basically guarantee the normal printing on the machine. The inspection of film flat screens is particularly important. Attention should be given to them. If something is inappropriate, the problems reflected in printed matter are uneven or dizzy.

Source: Printer