Screen printing oil painting

Oil painting has a long history in Europe. Due to its strong performance, it has formed a major painting species. With the continuous improvement of the people’s material and cultural life, more and more people are paying attention to the artistic atmosphere of the living room, and oil painting is undoubtedly an important choice. The oil paintings on the market include printed oil paintings, simulated oil paintings, Linyi oil paintings, and creative oil paintings. Among them, Linyi paintings and creation paintings are relatively high-grade, and their prices are relatively high. The people are still unable to afford them. Only screen printing simulation oil painting is favored by people because of its good quality and low price.
The oil painting is characterized by a thick, solid color palette, strong brushstrokes, a clear pattern, and expressiveness. One of the characteristics of screen printing is that the ink layer is thick, rich in layers, and strong in three-dimensional. Therefore, the use of screen printing can reproduce high-quality painting artwork and achieve real effects.
One of my manuscripts, "Self-operated Small Screen Printing Oil Painting Factory," was published in the 5th issue of Screen Printing magazine in 1999. There are many readers who telephone to inquire about screen printing techniques.
First, prepress image processing
1. The draft
The oil painting color draft is preferably the original or master copy painting, and the print oil painting can also be used because the computer processing can eliminate the original screen angle of the draft.

2. Make a positive picture
Oil painting originals use a professional camera or digital camera to use a scanner to directly input images on a computer. The computer's built-in “Color Uniform Translator” automatically compensates for the chromatogram between the scanner, camera, and screen, making the colors accurate and accurate. Quality Yang picture.

3. Yang picture size
A1 off 544mm×66Omm

A2 4 open 544mm × 376mm

A3 8 open 270mm × 376mm

A4 16 open 270mm x 188mm

4. Tonal range
The control screen printing feature gives a tone range of between 10 and 85.

5. Network type selection
Random nets, also known as FM outlets, such as diamond outlets and crystal outlets, belong to FM outlets and have the following advantages:

The same dot size but uneven distribution, much smaller than traditional dot

No dot line, no angle;

The level of the image is represented by the density of points rather than the size of the points;

There is no worry of misalignment and interference with moire;

Can faithfully present the fine texture that traditional dots are not easy to express. Currently, inkjet printers basically use FM dots.

Relative to FM network points, traditional network points are called AM sites. The characteristic is that the frequency (point spacing) is fixed and the amplitude (point size) changes. Because the amplitude of the amplitude modulation network is fixed, the fixed point arrangement is generated. Therefore, there are restrictions on the network line and screen angle.

AM point should be selected chain points and circular points better.

6. Screen lines
45~65 lines are suitable for screen printing artwork.

7. Output angle
Portrait painting with warm colors as the main screen angle
Yellow Edition 90° Magenta Edition 45° Youth Edition 75° (15°) Black Edition 15° (75°)

Landscape with a cool color as the main screen angle
Yellow Edition 90° Magenta Edition 15° (75°) Youth Edition 45° Black Edition 75° (15°)

8. Precautions
Unlike screen printing and gravure printing, screen printing must use positive images and the film is on the front of the film.

Second, screen production
The best selection of aluminum alloy frame, can also be used to frame the quality of Chinese fir. The screen is made of medium-thick orange polyester single screen with excellent stability. The number of outlets must match the mesh number of the screen, and the ratio is approximately 1:4. That is, 60 lines of screens should use 25-300 mesh screens.

Use a mechanical stretch net or a pneumatic stretch net. Stretching slowly when the tension increases, usually a good quality screen, after more than 3 days, should not be rushed, otherwise it will cause inaccurate. The stretching method is as follows:

At the beginning of the first day, the net is pulled to 70% of the rated tension to eliminate the curling of the screen and smooth the screen;

The next day, pull the net to 70% of the rated tension, and avoid pulling it tightly in place. High tension sometimes causes net breaking.

The third day of incremental pull to the rated value, using a tensiometer to measure the tension value, about 20N/cm or so. Retension the area where there is not enough tension until the tension is stable at the rated value. Finally, tighten the tight screen and mesh frame. After stretching the mesh frame for at least 24 hours, wash it with washing powder and detergent. Rinse both sides of the screen with clean water, and dry it after drying with a hot air blower.

The tension of each version of the four-color screen should be approximately the same.

Diazo emulsion is made of oily ones. Try to use photopolymers with short printing time and high resolution.

The size of the scraper bucket should be selected according to the size of the screen in the frame, and the length of the scraper bucket should exceed the screen size by 2 to 5 cm. If a short scraper bucket is used, it is difficult to avoid overlapping of the joints, resulting in uneven thickness of the film. The thicker part of the film may cause film floating, peeling, sagging, etc., making plate making difficult or difficult to repair.

The first time the squeegee should be scraped once on the printing surface; the second time it is scraped once on the printing surface and the squeegee side; the third time the front and back sides are scraped once to meet the requirements of the general print number. In special circumstances, if the painting requires a thicker layer of ink, then the number of squeegees should be increased and then dried or dried with a hair dryer.

Attach the transparent cross-rule line sticker to the platen. After aligning the cross-line of each image with the reticle of the platen, place it on the glass with transparent tape and place it in a dry place. The screen frame is positioned on the sensitization table, and the screen and the yang image can be exposed at regular intervals. Four-color Yang picture pattern darkness is not the same, the printing time is not the same. If the copying time is too long, it will result in the difficulty of stencil printing. If the printing time is too short, the stencil will be washed out easily. It takes a few experiments to get accurate print time. It is best to use a “photosensitive test board” with several patterns of different light transmittance. Take them out and print them directly. After the development process, you can know which pattern has the best light-sensing effect. Then according to its specifications, you can get the correct drying time.

The dried screen plate is placed in water and soaked for a while and shaken so that the film surface pattern gradually emerges. The pressure nozzle can then be used to clean the pattern and the pattern can be clearly displayed. Rinse both sides of the screen until no softened photoresist is left. Dry the screen, repair the pinholes, and re-exposure to increase the durability of the screen.

Third, the printing process
Screen printing oil painting selected paper, canvas, Chevron board and so on.

Four color transparent ink M magenta, Y yellow, C green, K black overprint, you can get the original color effect. Before using the ink, add 5%-1O% thinner and stir it thoroughly. The maximum amount should not exceed 20%. Too much thinner can affect the printing effect.

The printing site should have air-conditioning equipment and keep the environment clean. Prior to printing, oil painting paper, canvas cloth, and Chevron board should be wiped with static electricity or static electricity, so as not to block the screen plate caused by dust fibers.

The amount of ink scraped on the paper depends on the dynamic pressure of the squeegee. The hardness of the scraper is 7O~75, the corners should be vertical and the length of the scraper should be 2~3cm on both sides of the screen. Squeegee angle of 45 °, pressure and speed to master their own, the net distance is generally less than 2mm, if the screen has enough rebound, we must make the necessary adjustments in time, ink back after the scraping should be uniform.

Printing skills
According to ink nature requirements: opacity printing ink priority printing, screen printing color sequence should be: blue - yellow - magenta - black.

According to the original tone requirements: If the landscape painting original tone is partial green, then cyan should be printed; if the portrait painted original tone is reddish, the red should be printed.

According to printing adaptability: If the substrate is easy to stretch, then a small area is given priority to printing.

The key to the quality of printing is the accuracy of registration. Four-color screen printing crosshairs must be consistent and must not be misplaced.

Finally, as long as a little modification, in the highlights of the picture with a hand-painted push ink, or painted with a plastic gel convex, to achieve real effects.

Screen printing a good oil painting simulation, whether it is in the draft, Yang pictures, stretch net, printing version, or printing and other links are required to be quite high, one of which does not meet the requirements will come to naught.