T-shirt printing pre-press process (1)
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Some people say that traditional printing has entered the era of low profit, and printing companies are moving from production to service. Personalized digital printing, personalized printing has gradually entered our lives, these two documents will tell the readers about the pre-press process of T-shirt personality printing.
First, the basic knowledge of T-shirt design
T-shirt design (pattern design) has active design and passive design. The active design is mainly used to produce commodity T-shirts. The designer exerts subjective creativity without any restrictions. Basically any object or any graphic art technique can be used for the creation of T-shirt patterns. Passive design mainly refers to the creative design of advertising T-shirts, travel T-shirts, commemorative T-shirts, etc., subject to certain restrictions, to be carried out under the constraints of certain intentions.
T-shirt design must first master the basic process of T-shirt printing, as well as the producer's printing technology and the T-shirt printing equipment used. For example, T-shirts with colored fabrics have been printed with water-based glue coatings, but if the producers master the production technology of thermosetting plastic inks and purchase the corresponding equipment (mainly T-shirt printing machines, infrared dryers, Infrared T-shirt ovens, etc., he can use the thermosetting ink to print the color fabric T-shirts. The glue printing and thermosetting ink printing have different requirements on the design of the pattern. The glue can only be printed with a simple color block pattern, and the thermosetting ink can be printed with a screen transition tone, not only on a white T-shirt. The original color screen printing can also be carried out on the dark T-shirt for spot color screen printing. If the pattern designed by the designer does not match the technical process mastered by the producer, the printed pattern will not reach the original intention and effect of the designer, or even print at all. Therefore, T-shirt designers must be masters of T-shirt printing technology, especially excellent T-shirt designers will pay close attention to the development of the world's latest T-shirt printing and printing equipment and its technical features, so as to Fast speed uses the latest scientific and technological achievements to produce new and unique T-shirts.
In industrialized countries, T-shirt designers are often independent professionals. They founded their own T-shirt designers or companies who sold their ideas and designs to T-shirt factories, T-shirt operators, advertising companies and more. Such T-shirt design companies often consider three issues when designing: 1. Customer requirements; 2. Using the latest T-shirt printing technology to achieve unique artistic effects; 3. Best cost profit margin.
Color tone screen printing technology has been popularized in China in recent years, and the screen printing technology has gradually been adopted in T-shirt printing. At the same time, the popularity and competition of the computer desktop publishing system has greatly reduced the production cost of color separation and screening. Now we have to make color separation and net film is very convenient and very cheap. This progress is like printing from letterpress printing to offset printing in the printing industry. T-shirt designers have got rid of the design restrictions of color block patterns (except for glue printing), and have a larger creative space, whether it is photo effects or painting effects. Or the inkjet effect can now be easily reproduced on the T-shirt through the screen printing technology. This is an advancement in contemporary technology, and it also requires T-shirt designers to master digital technology.
Second, the production of the draft
The plate-making manuscript can also be called a black and white manuscript, a color separation draft, a plate-making negative film, and the like. Its main function is to make a photographic printing plate. Therefore, the plate draft must be drawn on a light-transmissive substrate. The image is an opaque ink layer (black or red), the transparency of the substrate and the shading of the ink layer. Density is a key indicator of the quality of a plate. The formation of the image of the plate is mainly made by hand-drawing, manual or mechanical drafting, photographic copying, laser photo-alignment, printer printing, etc., but it is also used as a plate-making draft after the ordinary paper is light-transparent (such as oil). .
1.Color separation
There are two main types of color separation: spot color separation and primary color separation.
Spot color separation refers to the use of any specially-adjusted color as a single printing color, and a plurality of spot colors are color-printed to form a color image. The five sets of color printing and twelve sets of color printing that we usually talk about mean that five color spots or twelve spot colors are sequentially overprinted to form a color image printed product. However, the number of spot colors is not equal to the number of colors in the image, because spot colors can also be overprinted, so five spot colors can also print six or even seven-color eight-color patterns. Spot color printing is mainly used for color block printing, and its reflection on the natural scene can only be simulated rather than restored, which is the biggest difference from the original color printing. However, with the development of screen printing technology and the development of new inks, spot color screen printing has sprung up in recent years, especially in T-shirt printing, the most advanced T-shirt printing technology in the world. It is not a primary color printing but a spot color screen printing, that is, multiple sets of color spot color screen printing on color, especially black T-shirt.
Primary color separation refers to the decomposition of the natural color image into three primary colors (magenta, cyan, yellow), in order to carry out the three primary color price printing to achieve the purpose of restoring the object image. Any color in nature is composed of three primary colors, so theoretically, the use of cyan, magenta, yellow, three color plates can print realistic reduction images, but due to various factors, the three primary color prints are difficult to achieve. This is true. Therefore, four-color printing is commonly used in printing practice, that is, three primary colors plus black. In recent years, in order to restore color more realistically, six-color printing and seven-color printing have been developed on the basis of four-color printing. The principle is to combine the colors of orange, purple and green on the basis of four colors. Separated to reduce gray scale in printing to achieve high fidelity. In order to distinguish from spot color printing, usually, the reduction printing which is performed by color separation of natural color patterns by optical or digital technology is called primary color printing (can be understood as reducing color printing), and it is optical and color. The concept of the primary colors (only the three primary colors) is different.
It is worth mentioning here that primary color printing and spot color printing are not incompatible. In the international arena, the latest development of color printing is the combination of primary colors and spot colors for exclusive primary color printing. It plays the role of both, complements each other, has more advanced printing effects, and belongs to fine printing. This has also been allowed to play in the T-shirt printing. I have seen an American-made T-shirt with a total of 12 colors. In addition to the four primary colors, there are also eight sets of spot colors. In addition to gold and silver, there are also foam printing and crystal pulp printing. Not only is the three-dimensional feeling strong and the special parts are shiny, it is amazing.
Professional T-shirt designers generally design and compose the picture according to the principle of spot color or primary color. After obtaining such a design draft, it is only necessary to perform color separation according to the requirements. However, there are also some non-special color designers or customers who only provide originals such as various pictures or drafts and require them to be printed on T-shirts. In this case, we need to communicate with the designer and the customer: First of all, we must understand the intention of the creation, what effect should be expressed, in order to achieve this effect is to use the special color printing or the original color printing? Even a special primary color print? At this time, T-shirts with different printing methods should be provided for them to understand and choose. Secondly, they should be told the cost of the production of the spot color printing and the primary color printing, so that they can make decisions based on their investment plans.
2. Separation and printing
The color separation plate is used to sensitize the corresponding color separation screen. The quality requirement is that the substrate has good light transmission performance, the second is high image shading density, the third is the alignment accuracy between the color separation sheets, and the edges of the image lines are neat and tidy, and the dots are full and clear.
(1) Multi-color color separation film positioning is generally based on the cross line, but in the process of printing, it is often easy to reverse the color separation film, or the front and back sides are wrong, or the graphics are upside down, we use the left positive The right oblique method hits the position crosshair, that is, the left side is + and the right side is x, thus eliminating errors.
(2) Since the red tear film is relatively expensive and not easy to purchase, it can be replaced with red self-adhesive paper. As long as the red self-adhesive is only attached to the PVC film (on the original or the line draft), it can be engraved with a knife. Since the red self-adhesive paper is far less translucent than the red tear film, the lighting of the light drawing table should be brighter. In this way, the price can be low, the shading effect is good, and the lines are smooth and clean, not afraid of water and moisture. What is even better is that it is easy to modify - as long as the re-engraving can be removed, and the red tearing can not be re-engraved, ink painting Only minor modifications can be made.
(3) If the patterns of the two printed color plates are not connected or overprinted, consider drawing two color drafts on one film, drying two plates when printing, A version closed B pattern, B version closed A pattern. You can even make a plate, add a strip of ink between the AB patterns, and print two colors at the same time.
3. Manual drafting
Hand-made manuscript is the most basic traditional method, mainly for hand-drawing and hand-drawing.
Hand-made drafting tools mainly include: lighting drawing table (OA table), drawing ink pen, drawing compass, triangle board, curve board, engraving knife, steel ruler, drawing PVC film, PCV film drawing ink, red tear film, red Self-adhesive paper, etc.
T-shirts must be hand-made. First, there must be a light-drawing table. The light source is usually a fluorescent lamp. If an incandescent lamp is used, you should use frosted glass or a layer of copy paper under the glass so that the light is softer and does not hurt your eyes. If you want to draw at home or in the temporary field, the emergency method is to put the square stool on the ground, put a piece of glass on the four legs, and put a table lamp under it, you can use it.
Drawing ink pen, mostly using a needle pen, the diameter of the pen head is 0.2 ~ 1.3mm. In order to prevent the pen head from being clogged, a hollow cotton (or sponge, etc.) can be placed in a bottle, and a half bottle of water is added. When the drawing pen is deactivated, the pen is inserted into the bottle, so that the pen tip is no longer blocked.
The steel ruler is used for engraving red tear film and self-adhesive paper. When drawing with a triangular plate, a curved plate, etc., the beveled side should be facing down to prevent the ink from being towed by the ruler.
The general drawing ink cannot be used to draw the diaphragm because it is slow to dry, has poor fastness, and is wetted by water in the rainy day. It is best to use a special film drawing ink to draw the PVC film. If you can't buy it for a while, you can also use a gel ink instead, but you need to lick it to concentrate. When applying a large area graphic with a gel ink, pay attention to the ink layer not too thick to avoid cracking.
Always wash your hands with soap before hand-drawing, as the grease on your hands will affect the ink application.
Draw according to the paste used and the order of overprinting. The printing paste has a hiding power, so the graphic contact lines of the respective color drafts can be overprinted, and even the light color draft can be used as the base color of the dark graphics. If the color of the fabric is darker, you can consider the white background. The drawing sequence of the glue printing color separation draft is exactly the opposite of the printing process, that is, the dark draft is drawn first, then the light color draft is drawn, and finally the white draft is drawn.
The water slurry is mainly used for printing white T-shirts, which is a transparent printing coating. Therefore, the overprinting of the color lines between the color drafts is 1 to 2 mm. If the overprinting is too much, the composite color of the two-color overprinting is likely to occur. The order of drawing is to first draw a color draft with a contour (usually black), and then draw the draft from light to dark based on this diaphragm.
The color separation sheet of the foamed printing plate should leave room for the expansion of the foaming pulp, the high foam is about 1 to 2 mm, and the low foam is about 0.5 to 1.0 mm.
The basic requirement for hand-painted (engraved) manuscripts is that the lines are smooth, smooth, and smooth, and the ink drafts that are drawn must generally be trimmed with a knives, especially at sharp corners.
4. Computerized digital production
With the development of computer technology and production, computer digital design, drafting and drafting have become quite popular in China. Compared with hand-painted manuscripts and photo-productions, it has the advantages of higher quality, faster speed, more convenient production, and lower cost. Especially the quality of color separation and screening is much higher than manual and The level of optoelectronic production has become a widely used production method.
The design, color separation, screening, and filming of T-shirt patterns on the computer must be completed by operating professional graphic design software and publishing software. General-purpose software such as Adobe LIIustrator, photoshop, CoreIDraw, etc. are mainly used for the design and production of image texts, but it is more convenient to use domestic professional screen printing and publishing software such as Wenyuange and Mengtai.
The program for digitizing the T-shirt pattern by computer is generally: graphic input - design editing - effect color draft - color separation - screening - setting the screen angle - output. If you hand it to a professional to make, you must tell some technical requirements: First, the intention of color separation. Whether it is primary color separation or spot color separation or special primary color separation, etc., must be clear to the production staff. Second, the network. The T-shirt printing screen is generally 60 lines or less, and the limitation on the number of screen lines depends on the production characteristics of the printing material, the texture of the fabric and the color. Glue printing is usually not suitable for screen printing. In special cases, screen printing technology is adopted, and the number of screen lines should be below 40 lines. The number of screen lines for water jet printing is generally about 50 lines. The number of screen lines for hot melt ink can be selected between 35 and 60 lines. If the fabric color is darker, the number of lines from 35 to 45 can be used to obtain a strong ink hiding power. The number of foamed ink and crystal ink added should be coarse. Should not be thin, the number of lines on the white background should be thicker than the number of lines in other colors. Due to the never-plugging characteristics of the hot melt ink, a 70-80 line screen can also be used. The dot pattern of the T-shirt print usually adopts an elliptical or circular dot. Third, the angle of T-shirt screening is generally 15: usually starting from 5`. The screen angle of the seventh color starts at 20' (still 15' apart). Fourth, in particular, please pay attention to the production staff, to take out the positive positive picture, which is different from the usual printing plate.
The main methods of output are:
(1) Printer drafting. Inkjet printers, laser printers, and wax printers can be used. Laser printers are expensive to purchase but have a lower cost of use. Inkjet printers have lower cost of purchase but higher cost of ink, and wax printers (also known as dry printers). The cost of acquisition is high. In terms of the quality of the film being drawn, the wax printer is the best, the laser printer is also good, and the inkjet printer is poor.
(2) Engraving machine engraving. That is, the computer engraving machine is used to engrave the pattern on the red (black) self-adhesive paper and then attached to the PVC film, but the accuracy of the engraving machine is not as good as that of the printer, and can only be used for printing with low precision.
(3) Laser phototypesetting. Laser phototypesetting is the method of making the highest quality film. Just because the laser photo-alignment equipment is quite expensive, only the plate-making center with a certain scale will be configured. Therefore, the edited software is generally sent to the plate-making center for filming. The price is higher than the printer draft, but the quality is much better.