Screen printing, or screen printing, commonly known as silk paint printing. Its basic principle is template. Its origin, like woodcut, can be traced back to the distant past and even prehistoric culture. According to documents, primitive people in ancient times printed human hands on stone walls by means of inkjet printing (Figure 288a), which is the most primitive and earliest stencil printing.
China is the first country to apply stencil printing to printing and dyeing industry. According to records, during the great cause of the Sui Dynasty (605-6 16), the court dresses were all printed with perforated plates. With the passage of time, this kind of stencil printing and dyeing, which was originally enjoyed only by rulers, gradually spread to the people. During the Ming and Qing Dynasties, this printing and dyeing technology has spread all over the country, and finally formed a perforated blue printed cloth with national artistic characteristics (see the section on paper perforated board). This carving technique was introduced to Japan from China in the12nd century, and it was further developed in Japan. As we all know, a common problem when carving orifice plates is that each "shape" (called "island") must be connected by a "bridge" (as shown in Figure 288), otherwise it is impossible to connect each shape together to form a layout. This kind of "bridge" frame is suitable there, which has a great relationship with the aesthetics of orifice graphics. "Bridging" was called "broken section" in ancient China. Later, I replaced this "bridge" (or "knot") with hair or silk thread. When shaving like this, the hair and silk thread are almost unaffected. Today's screen technology is based on this method. As a plate, the screen whose grid is blocked is the "island" that exposes the grid, which is the "bridge" (Figure 289).
Fig. 288 schematic diagram of plugging material of orifice screen
Figure 288a The handprint (negative image) of prehistoric humans on the cave wall is about BC 1585.
Fig. 289 Schematic diagram of screen leakage hole
Fig. 290 B. Xie An's Everything is Beautiful 1965 screen version (76x 1 17).
In the west, stencil printing has been used in commerce and decoration for a long time. Such as billboards, fabric printing and dyeing, wall painting and some utensils spraying. Sometimes this method is used to print velvet paintings and make fine arts works by school students. At the beginning of this century, Samuel Simon, an Englishman, invented screen printing and kept it a secret for several years (1907- 1 9 15). Later, due to the special needs of the military industry, this technology was patented in Britain and the United States. However, artists and printmakers don't think so. They don't have the enthusiasm of early artists for woodcuts, Merutin and lithographs. On the contrary, they avoid and reject them. One of the important reasons is that some print agencies and award-winning groups often refuse screen prints to participate in art exhibitions on the grounds of vulgarity. The 1930s was the most depressed period in America. Thanks to the efforts of the Art Planning Department of the Federal Work Development Agency, a group of artists led by Anthony and Veronica used silk screens to practice their artistic purposes. Compared with copper plates and lithographs, a complete set of screen printing equipment can be built at low cost, which is extremely beneficial in the United States in difficult times. For this reason, in the 1930s, some outstanding artists in the United States, such as Ben Shahan, Robert Gowasme, Harry Robert Jeffrey Sternberg and other artists with social conscience, transferred their talents to the practice of screen printing and re-evaluated screen printing, a method that has been overused by business.
As a special pursuit in art, screen printing greatly improved its position in the art world and people's prejudice against it, which enabled it to develop and influenced a group of artists in the 1950s. They include abstract expressionism and activism, such as Jackson Pollock and Duchamp.
From the late 1950s to the early 1960s, due to the new concept-driven pop art movement and the application of photographic plate-making, screen printing was widely recognized and loved, and was dubbed as avant-garde media. A group of artists in pop art, such as "discovery", "op art", "hard edge", "stripe", "color gamut" and "logo painting". They are all committed to screen printing, using the most popular media as creative materials and using collage methods to express them. At the same time, because the screen version can adapt to the printing on three-dimensional objects, it breaks the established boundaries between painting, sculpture and printmaking. In this movement, the famous artists are: Robert Rosenberg, James rosenquist, andy warhol, roy lichtenstein and so on.
Due to the development of economy and technology, the application of nylon or stainless steel screen and the improvement of power system, it is possible to produce and copy hundreds of dry screen prints, thus affecting the value and reputation of screen prints. In addition, because most of these screen painters don't make their own works in person, they hand over the drawings to screen printers for printing, which leads to the dispute whether they are "original works". Because it has become thousands of copies, the author can't sign them one by one, thus increasing his doubts about it. This is an important reason why the price of screen printing has been fluctuating in the west. In other editions, there has been a precedent of division of labor between painters and technical masters, but this is also the reason why printmaking is used as a tool in the printing industry. Nowadays, the division of labor between artists and technicians in screen printing and other printing types has become a profitable means, which can not but devalue printmaking. Of course, there is no need to make it a cheap medium for the public and popular all over the world.
Screen printing, as a form of printmaking, has risen in China in recent years, but as an industrial screen printing, it has long been very common in China, such as trademark, advertisement and textile printing in printing and dyeing factories. However, because there is almost no print market in China at present, the development of this kind of screen print which is convenient for mass production still needs the economic take-off and the improvement of material and cultural living standards.
2. Equipment and materials
Screen printing equipment is very simple. The most basic thing is that a wooden frame with a screen (that is, a screen frame) connects one side to a table with a jiaozi chain, which is different from a rubber scraper.
A. screen:
At first, silk was used as a net, and later it was developed into nylon, synthetic fiber net and stainless steel net. At present, silk screen is widely used in industry, but only a few are used to make prints for artists. Generally, we take synthetic fiber net as material benefit. This kind of mesh cloth is sold in major department stores, so we should have a choice when buying it. Generally used as printmaking, it is appropriate to choose 150 mesh (mesh, that is, mesh per square). )
B. framework:
Generally speaking, it is better to use straight wood that is not easy to deform, such as pine and Chinese fir. The battens used are 4×5 cm, which can be increased or decreased according to the size of the net rod. The structure of the wooden frame is shown in the figure. We should aim at firmness and fairness.
C. net value calculation method:
Generally speaking, the net can be nailed to the wooden strip soil at the bottom with a stapler. Pay attention to the flatness of the screen latitude and longitude lines when nailing the screen. As shown in Figure (292), the net can be tightened and nailed. After the screen frame is nailed, the four sides (including the inside and outside) must be sealed with wide tape (as shown in Figure 295) before it can be used for plate making and printing. When scraping in this way, the edge is straight and clean, which is also convenient for cleaning and reuse of the net frame.
D. Fixing method of screen frame and bedplate:
The simplest way is to connect the hinges of doors and windows with a twitching shaft, such as the opening and closing of doors and windows. When the shaft of the hinge is pulled out, it can be separated from the bed board. Another method is also very convenient (as shown in Figure 296). There are many ways, in short, it can be opened and closed when connected, which is convenient for disassembly, plate making and cleaning.
E. scraper:
It is the main printing tool for screen printing. Scraper can be made of mortar: use wooden boards (three-in-one or five-in-one) to clamp oil-resistant rubber strip with a general thickness of about 1 cm. As shown in Figure 294, the size of the scraper is slightly shorter than the short side of the screen frame (scraping from top to bottom because of scraping). Rubber strip's head of scraper should be ground straight with iron sand skin, and cannot be ground into bevel or circle. (as shown in Figure 294)
Step 3: manufacturing method
The production of screen printing can be roughly divided into three categories: first, engraving method, second, direct painting method and third, photosensitive method. But no matter which method, there is only one basic principle, that is, according to the draft or idea, try to block or leave holes in the grid, so that the pigment can leak out of the grid and fall on the printed surface, which is the graphics that the author needs.
A. cutting template:
Put the wax paper (wax paper, which is a kind of soft film paper based on sulfuric acid paper or polyester sheet, or coated with a layer of copy paper) special for screen printing industry on the drawing or directly carve various patterns on one side of the paint film with an oblique knife (using hacksaw or razor to carve paper or a white oblique knife) (be careful not to break the paper base), and then cut the paper base with a knife tip. After carving, put the screen on it (pay attention to the alignment position), then gently wipe it with gauze dipped in banana oil, dry it with clean gauze and press it tightly, so that all required paint film patterns are attached to the bottom of the screen. It takes half an hour to remove the paper base and complete the plate making (credibility printing is similar to this method). Hole engraving is a traditional method of screen printing. In the paper printing part, the above-mentioned paper engraving method is to engrave holes with thick paper and directly print printed matter. If you use thin and tough paper, carve various patterns and stick them on the net with glue or ink, you can also achieve the purpose of making silk screens.
Fig. 299. Apply photosensitive adhesive on the web with a scraper.
B. direct coating method:
There are many kinds of sealing materials, such as glue, wax (transparent spray paint), gouache, shellac paint (also known as foreign dry paint, which can be dissolved in alcohol) and medicinal ink (or thin ink). Some of these materials are soluble in water, while others are waterproof ... Knowing this, you can freely use different plate-making methods.
Example: paint with glue (or glue and water powder pigment) on the internet, brush the whole net with shellac paint after drying, and wash off the glue part with warm water after drying, and the plate is made. On the contrary, if you paint with shellac on the Internet, brush it with glue when it is dry, and then wash it with wine and semen after it is dry, you can also make a screen version. This positive and negative exchange plate-making technology has similar methods in lithography and gravure technology, which can be used for reference.
In addition, this method can also use wax, medicinal ink, crayons, glue and so on to make pages. However, we must pay attention to one thing: for the screen board made by sealing the screen with glue, the pigment used for printing can only be oily, while the glue solution for sealing the screen will be washed away when printing with water-based paint. In addition, in order to prevent the glue from cracking after drying, a little syrup and a few drops of glycerol can be added. This is the same principle as the sugar water method of copperplate prints and the one-page glue leakage prints.
In addition, there is a direct coating method by wiping wax, just like physical rubbing (see physical printmaking). That is, under the net, brush with crayons against various physical textures, then brush with glue and wash off the crayons with gasoline, and you can get screens with different textures or various objects.
C. photographic photosensitive method:
Use a bucket scraper (see Figures 298 and 299) to coat the emulsion on the screen, and then stick the black and white artwork (or photographic negative) on the film for exposure. After exposure, the emulsion hardens and fixes the screen, blocking the mesh. The unexposed parts can be washed away with water to expose the net. This is the basic principle of photographic sensitivity, just like convex, concave and lithography. For details, please refer to the section on layout photography. (Figure 300- 1-8)
Figure 300 Production process of photosensitive screen
Fig. 30 1 schematic diagram of photographic screen photosensitive bidirectional daylight printing schematic diagram of optical printing
Compared with other versions, screen printing is simple and light. Scrape the material evenly from top to bottom with a scraper. When scraping, there should be a gap between the screen and the pressure plate for spreading paper, so that when scraping, the screen will automatically bounce up after scraping, and the pigment leaked on the paper will not overflow the graphic boundary.
At present, there is no pigment for screen printing in China, so most of them use painting pigments and printing inks, but they can only be used after modulation. Oil painting pigments and inks need to be diluted with colored oil or turpentine. Waterborne pigments need to be mixed with glue or paste. Silk paint, commonly used in business before, can also be used to print printed matter, which has a heavy feeling.
In order to print every printed matter in the center of drawing paper, cardboard can be used to make positioning marks on the table under the net.
The method of color matching is the same as other plates, but the method of plate alignment can use transparent polyester sheets to correct the position, which is accurate and simple. The method is: put the polyester sheet under the net, fix one side of the net with adhesive tape, and then scrape and print the master on the polyester sheet. When overprinting, as long as you put the printing paper under the polyester sheet, aim at the master pattern, and then lift the polyester sheet aside, you can scrape it off the screen frame. In addition, cross marks, corner marks, etc. can also be used.
If it is necessary to keep the printed screen, the screen covered with pigment should be cleaned with water or kerosene for the next printing. After the oily pigment is printed, it can be cleaned with kerosene (or gasoline). When washing, you must put some old newspapers under the net to absorb the ink washed online. Waterborne pigments can be washed with water. If you don't keep the printed picture, you can make it into paste with industrial bleaching powder and put it on the Internet. Scrubbing with a steel brush after half an hour, and then rinsing with clear water. Another method is to use caustic soda banyan solution (50 grams of sodium hydroxide, dissolved in 300 ml of hot water), wear acid-resistant rubber gloves, and scrub the whole net with stainless steel cotton dipped in caustic soda solution. After about half an hour, you can rinse it with water.