Designers should know about screen printing

Often there is a dialogue about who is right or who is wrong between the designer and the printer. In many cases, the production department believes that “as long as the designers change their practices, they can print better.” The designers retorted: “I don’t know what that is.” Because the designers never go through the net. India training does not complain about them. In fact, designers should be encouraged to go to the production site and let them see the final printing effect of the entire job. The purpose of this article is to help designers learn more about screen printing processes and take more responsibility for the final print.

1. Responsible for printing orders

This may be contrary to the ideas of many printing companies. As far as personal feelings are concerned, if you do it yourself, you will know when you remember it. Designers should specifically specify the printing sequence, the number of screens, and the number of exposures, as shown in Table 1. If there are no other things, work in the platemaking, ink and printing production department for a few hours.

Table 1 Recommended screens, print sequences, and other labels on the film

Customer Name Job No. Ink Color Job Name Date Clothes Color Printing Position Screen Size Remarks Printing Color Sequence

2. Learn from the sample

Designers often say that they do not see the final finished garments. This is puzzling. Can the printing company not afford a graphic designer a production sample for them to study?

3. Determine the correct printing sequence

For printing on light-colored garments, the print sequence is usually from light to dark, or from the minimum amount of ink to the amount of large ink, because the ink sticks to the back of the screen, and dark colors are not expected to stain light colors.

Print on dark clothing, usually on a white background, or in the field or tone dot. This layer of white must be photocured and then printed on it in various colors. The typical printing sequence is from light to dark, and any large area of ​​the main color must be printed last, see Figure 1.

For true four-color screening (CMYK) jobs, YMCK color sequence is used. Any spot color must be printed after a similar primary color, such as red after the magenta.

4. Screen selection

This will vary depending on the type of job you are doing. In general, a simple design uses a 45T (45 lines per centimeter) screen. More complex work, screen up to 77T. For finer mesh tuners, 90 to 120 mesh screens can be used. Should use the screen mesh version of 77~90 mesh, use 120 mesh or finer screen printing the above color.

5. Clothing printing is not paper printing

Decompose a large pattern into large dots (55 lpi to 65 lpi), transfer these dots to the template, and then print these dots on the finished clothes, completely different from the paper printing.

Although some images can be printed using trichromatic inks, most jobs are printed in spot colors. On black clothing, printing without CMYK primary inks will be very dark due to printing on the background, and printing on a white background on screen printing with standard spot inks. This is the so-called "simulation" or "analogue" primary colors.

6. Design screen display and actual effect

The image you see on the monitor is fine, but the image on the screen is not what you will get. When screen printing, everything "expanded". This is the so-called "net expansion." If there is a 20% density area in the image, turn it into a 20% dot and print it out, the dot may expand to 40% of the original size, so that there will be almost 30% dot density on the clothing, in dark Adjusting the area will become even more serious. 70% of outlets may be printed on site (100%). In the color separation must be considered lighter, leaving room for a large number of network expansion, see Figure 2.

7. Printers can't relax

After seeing the proofs, sit in the studio and make some minor changes. This is easy to do. The fine adjustment of two or three colors means that two or three screen printing plates must be re-created, the old screen plate must be removed from the printing machine, the new screen plate must be installed, and the repositioning and test printing should be performed. It is not easy.

The matching color is the same, and it is not easy to make the small color patches printed on the glossy paper match the colors printed on the fabric as much as possible.

8. Have a common language

Dealing with designers every day, I found that there are two different languages. Producers will complain that "red" is not bright enough on black fabric, and it may be surprising that red is no longer bright. In fact, this has nothing to do with red. On black fabrics, red usually needs to be primed, probably because your background color is not bright enough, or the production staff needs to slow down the squeegee speed, use a lower mesh screen, change the squeegee angle, or use a comparison. The opaque white background color makes the background more bright, so that the printed red is brighter.

9. Limitations of the screen printing department

There is no reason to expect that the screen-printing department can make 2% of the screen points on the screen. This can't be done, but individual people can do it. Need to make a test film with different densities from 5% to higher, the platemaking department can print, let them print proofs and see what the results are. At the same time, if the tension of the screen plate used by the plate making department is not suitable, the dot gain obtained may be as much as 50%~60%, and this should be taken into account in the mesh modulation version.

If the screen printing shop can not guarantee accurate overprinting, consider overprinting black and other colors in the 2 to 4 positions of the spot color job.
The above are some of the issues that designers should consider when making screen prints.