Article: Printing knowledge that designers should understand
From the public number: Study set
As graphic designers, we do not need to master too professional printing knowledge, because after all, printing and design are two independent jobs, but the two are closely linked. It is still necessary to understand the relevant knowledge and process of printing, which helps us to consider whether the finished product can be realized in the early stage of design, which has guiding significance for cost control and process selection. So what printing knowledge do designers need to master? This issue will answer your questions.
The color model of printing equipment such as desktop printers, printing presses, and inkjet printers usually uses CMYK, which is one of the models that describe color, which is equivalent to the fact that we can describe an "apple" in the language of different countries. CMYK is short for cyan, magenta, yellow, and black initials, black Black changed to K to avoid confusion with RGB Blue, and computer displays, TVs, mobile phones, projectors, digital cameras, scanners, etc. are all color models that use RGB. Similar models include LAB and HSB.
CMYK is the pigment color that absorbs light, and the three primary colors mixed with the pigment are black, which is the opposite of the three primary colors of light and is the complementary color of RGB. Three primary colors can be obtained by mixing most of the colors, although theoretically three colors can be derived from black, only three kinds of CMY inks are needed, but because the current manufacturing process can not create high-purity inks, the result of CMY addition is actually a dark red. Therefore, black ink is added to form a four-color process color.
Polychromatic black, or rich black or jet black, is a cmyk four-color overprint. In order to make large areas of black more intense or to correct black ink often warmer, polychromatic black is usually used. The CMY value does not have to be set to 100, and the more common way is to add a small amount of C (cyan) to complement the warmer black in the case of K90-K100. This also makes it less difficult to color chromatic. For text, you basically need to choose monochrome black.
Instead of synthesizing colors through four colors, they are printed specifically with a specific ink. Any color can be converted into a spot color, the above picture is the contrast between the four colors of the synthesis of green and spot color green, the spot color ink coverage is strong, has opaque properties, and is more colorful than CMYK in terms of color. In terms of cost, spot color printing will also be more expensive.
We can quickly query the spot color effect through tools such as pantone color cards, and there are corresponding pantone color libraries in the software. Using spot color printing colors, color is more able to ensure the accuracy of colors in printing than four-color inks. We can also choose spot colors that CMYK can't achieve, gold and silver as well as fluorescent colors to enrich our designs. The gold and silver mentioned here have a reflective texture, which belongs to metal ink, also known as printing gold and silver, but it is still different from the metallic texture of hot stamping foil or gold leaf cardboard.
In the color picker of the software, we often see small triangles and cubes next to the color, what do they mean? The triangle exclamation at the top indicates that the currently selected color is beyond the printable range and gives the recommended color below the triangle, while the cube below indicates the closest color the current color can display on the Web.
Because the color range of process colors is limited, when we want to show bright and beautiful colors in the computer, we need to choose fluorescent spot colors to express. The fluorescent color printed out is a spot color ink with a fluorescent agent added to the ink, and the fluorescent ink will appear more vivid and eye-catching than the dim color of the four colors. The disadvantages are that the price is expensive, the shelf life is short, and the color control is not easy. It is basically difficult to standardize printing without producing chromatic aberration.
The traditional film output has been replaced by a computer direct plate making system (CTP), which needs to decompose the graphic picture into a monochrome printing plate when printing, and how many plates (including spot color plates) need to be produced as many chromatic plates. The material of the plate is an aluminum substrate, on which there is a photosensitive material, when the photosensitive resin in the photosensitive material is heated and decomposed and polymerized for imaging under the illumination of infrared light, it forms a graphic.
From ink to carrier to technology, there are many ways. Each of the above printing technologies has its own advantages and characteristics, in addition to differences in production costs and so on. The speed of printing and the expressiveness of color, as well as the ability to print in batches, are also different. Different printing methods produce different printing effects. In order to ensure the final expressiveness of the finished product in the design process, the later process application and the time and cost of controlling printing should be considered in advance.
Lithography is the use of water and oil incompatibility principle to achieve printing, the printing plate on the graphic area of the lipophilic hydrophobic and blank area hydrophobic oleophobic. Using indirect printing, the ink and water on the plate are transferred to the rubber roller by pressure, and then the inked roller is embossed onto the paper. Lithograph offset printing occupies a major position in the mainland printing industry, which is characterized by multi-color overprinting, bright colors, large printing format, less noise and stains, and the advantages of flat screen. Print quality is not degraded by continuous high-speed printing operations, and is suitable for high-speed operations in large quantities.
Letterpress printing is similar to the principle of stamping, because the blank part is lower than the ink part of the printing, so the blank will not be attached to the ink when embossing. Since the graphic and text parts are not in the same plane as the blank part, the blank part printed to the paper surface by pressure will be slightly raised, and the part with ink will be convex downwards. Letterpress printing technology is the first printing process widely used in commerce, in the early days, only movable type printing text information can be used, and so far, image engraving plates can also appear in letterpress printing.
Intaglio printing is the opposite of letterpress printing, where the part of the graphic is lower than the blank part. The degree of depression will change with the level of the picture and text, and the amount of ink in the depression will make the ink on the bearing paper more layered in thickness. When printing, the entire page is coated with ink, and then the blank part of the ink is mechanically scraped off by the ink scraping.
Screen printing originated in China more than 2,000 years ago, and its principle is that the mesh of the graphic part of the printing plate is through-hole, while the mesh of the blank part is blocked, and the ink is squeezed into the mesh through the scraper and transferred to the paper to obtain the same printing content as the original. It belongs to the well plate printing. Screen printing cost is low, equipment and operation is simple and easy, and the applicability is strong. The size of the printing plate is not limited, which is incomparable to other printing technologies.
Digital printing generally refers to the technology of printing materials directly from a computer or output device to produce a printed product. Digital printing usually uses millstones, and although the finished product is brightly colored, it is not suitable for long-term preservation. At present, the printing quality and cost are higher than traditional printing, and compared with traditional printing, the rapid delivery of digital printing has obvious advantages. It is the first choice for printing proofing, it should be noted that although the color is bright and bright, there will be uneven performance when printing in large areas.
Inkjet printing is a "non-contact with the carrier" printing form, it has no pressure and printing plate, the information in the computer can be entered into the inkjet printer to print. Because it is not limited by materials, it can be printed on a variety of materials. Can be printed in one go, without the need for plate making and printing and repeating chromatic colors. The oil pump sprays the ink out at a certain pressure, and is often used in outdoor advertising, interior decoration and other fields.
Laser printers were born out of the laser illumination technology in the late 1980s, using lasers to quickly project graphics and text onto the surface of the photosensitive drum, and electronic charging occurs at the location of the beam, attracting delicate toner particles from the sensor to the paper surface heated by the high-heat drum. Toner is divided into blue, product, yellow and black colors. Laser printing has the advantages of fast speed and good imaging quality, but the relative cost is also relatively high.
Positive paper size originated from the printing standards of the Republic of China period, and early dictionaries, books, newspapers, etc. basically used positive specification paper printing. And Dadu paper is an international ISO standard, originated from Germany, is also the current National Standard paper size in China, because the size is larger than the positive paper, so it is called Dadu paper. The so-called open number is the meaning of cutting in half into several parts. At present, positive degree and large degree paper are commonly used printing paper sizes in the printing field, mainly used in printed finished products.
Adopted in 1922, three sets of paper sizes A, B and C were defined, including the well-known A4 paper size, which is the internationally accepted three sizes. Derived from a series of standards developed by the German DIN. This standard is used by many printers and design software, and is widely used in printing and design fields. Taking the A series as an example, A0 is cut half as A1, A1 is cut half as A2, and so on. The series dimensions have a constant aspect ratio that will always maintain the same aspect ratio no matter how many times the average fold is passed. Among them, A3 to A6 and B4 to B6 are commonly used specifications for copy paper.
Paper
Art Paper, also known as coated printing paper, is called chalk paper in Hong Kong and other regions, and is called Liguang paper in Taiwan, which was translated as fine art paper in China in the 1930s. It is a high-grade printing paper made of white paint on the base paper, which is divided into single copper and double copper paper, and because of the different calender surfaces, it is divided into bright and matte paper. It is one of the most used papers in the printing industry. It is mainly used to print the covers and illustrations of high-end books, posters, postcards, trademarks, etc.
Offset paper
Plywood paper is also called plywood printing paper, and the old name "Dowling paper" also belongs to the relatively high-grade printing paper. It is made of sizing on the base paper made of bleached wood pulp, divided into single-sided offset paper and double-sided offset paper, offset paper is mostly used for color prints, in order to make the ink can restore the hue of the original manuscript, it is required to have a certain degree of whiteness and smoothness. Offset paper has uniform absorption of ink, strong water resistance, density and printing effect are worse than coated paper.
Letterpress paper
Letterpress paper is made from bleached stem fibers, a paper with no sizing or a small amount of sizing on the surface. Divided into 1 to 4 numbers, representing the degree of merit and inferiority of paper, the larger the number of paper, the rougher the paper, suitable for important works, scientific and technological books, academic journals and college and secondary school textbooks and other body paper. It has the characteristics of uniform ink absorption, and at the same time has the characteristics of no lint, slight elasticity, slight water resistance, and certain mechanical strength.
White jam paper
White cardboard, also known as whiteboard paper, is a single or multi-layer combined paper that is completely manufactured and fully sizing by bleach chemical pulping, and is divided into two types: single-sided white background and double-sided white background. High toughness and hardness, not easy to break, characterized by high smoothness, good stiffness, neat appearance and good uniformity. It is mainly used in hardcover high-end books, high-grade packaging and promotional cards and hanging cards.
Copy paper
Copy is a transliteration of The English Copy, which translates to copy. It is a kind of high-end cultural industrial paper with considerable production difficulty. Copy paper is mainly used for printing multiple copies, suitable for copying and typing. It has high physical strength, excellent uniformity and transparency, and good surface properties, delicate, flat, smooth, no bubble sand, good printability. Due to the translucent nature of the copy paper, it is mainly used for the use of protective pages with portrait pages in book printing.
newsprint
Newsprint, also known as white newspaper, is produced from mechanical wood pulp or other chemical pulp as raw materials, contains a large amount of lignin and other impurities, and is not suitable for long-term storage. The storage time is too long, the paper will turn yellow and brittle, the water resistance is poor, and it is not suitable for writing. Suitable for newspapers, periodicals, textbooks, comic strips and other body paper. The paper texture is soft, the ink absorption is good, and the two sides of the paper are smooth and non-lint after calendering, so that the imprint on both sides is clear and full.
vellum
Kraft paper is usually yellow-brown in color, using sulfate softwood pulp as raw material, beaten and copied on a long net paper machine. Suitable for bags and wrapping paper, etc. Depending on the nature and use, kraft paper has a variety of different uses. Kraft paper is a general term for a type of paper, and there is no certain specification, generally classified according to its different properties and uses. It is used in chemical, machinery and other industries, especially widely used in the food packaging industry.
Special paper, also known as fancy paper, a wide variety of materials, made of different materials, is a variety of special purpose paper or art paper collectively referred to, special paper is a special purpose, the output is relatively small paper. The process varies, as decorative paper is widely used in fashion avant-garde packaging, prints, books, picture books, etc., but the price is relatively higher than that of ordinary paper.
The grammage of paper refers to the weight of paper per square meter, the same weight of paper, due to different materials, and different process technology, their size and thickness are not necessarily the same. The material of the paper is soft, the density is low and the paper is thick, the paper material is hard, and the high density is thin.
Gilding is a printing decoration process in which a metal plate is heated, foiled, and a golden text or pattern is embossed on the print. It is often used in book covers, gift boxes, high-end business cards, commodity packaging and other fields.
The principle of the hot stamping process is basically the same as that of the bronzing, but the materials used are different, with the impression of high-end and quality, and the pattern after the ironing is clear and beautiful, the color is bright and dazzling, wear-resistant and weather-resistant.
Ultra viole, meaning ultraviolet light, UV varnish is a method of curing varnish coatings using irradiation. It has been widely used in the gloss processing of printed materials such as book and magazine covers.
The graphics are engraved into metal plates, similar to the principle of seal engraving, and pressed onto the paper by instrument. Here you need to choose thicker paper to achieve better results, through the pressure to form a concave feel.
When the convex is pressed, a set of intaglio and letterpress corresponding to the yin and yang of the graphic are used, and the paper is placed in the middle position, and the relief-shaped concave and convex graphics are pressed out by applying a larger pressure. The bumping process has a vivid and beautiful three-dimensional sense.
The hollowing process is to use the principle of laser engraving to interact with the bearing to achieve the cutting, punching, scribing, shadow carving and other processing of graphics and text. Die-cutting is the process of allowing the laser to etch a pattern or cut a special appearance profile on the engraving. The application field is quite extensive and suitable for various scenarios.
Laser materials not only have a novel and bright appearance effect, but also have high-tech anti-counterfeiting functions, known as the world's packaging and printing industry in the most cutting-edge technology products. It is often used in commodity packaging, book albums and other fields.
Lamination is a layer of transparent plastic film on the paper meaning, belongs to a major process of post-press processing, classified by material, can be divided into light film and matte film, widely used, for printed matter, the use of lamination process in improving the aesthetics also has a protective effect.
Bleed position is a typographic term that refers to the part reserved to ensure the accuracy of the cropped image, which is specially extended to avoid the white edge of the graphic edge due to the error of cropping. We often say that the difference between the design size and the finished product size is that the design size is always larger than the finished product size, and the large range is the bleeding level. The bleed level is mostly set to 3 mm according to the process tolerance range, that is, the four sides of the layout are added 3 mm each on the basis of the actual size.
After setting the bleed level, you can carry out the layout design work, here it should be noted that the left edge of the image in the figure is stuck in the position of the bleed line, which makes the setting of the bleed lose its function, after cropping, the edge of the picture will still have a white edge. The right side zooms in beyond the bleed line and this problem is solved. In addition, as a text that needs to be read carefully, unless it is deliberately designed to be cut in form, the text needs to be as far away from the bleeding level as possible.
The resolution determines the fineness of the bitmap image details, for the print level of the picture, the resolution is basically required to reach 300 or more, in order to ensure the rich detail and clarity of the print. Too small a resolution can lead to blurry fonts, mosaics, and other situations that affect the quality of the layout. After creating a good picture size, the first thing to pay attention to is the resolution problem.
The resolution is not the higher the better, for the need to hold in the hand of business cards, books, postcards and other printed materials, very close to the eye of the picture, the need for higher resolution and details, for the early computer in the display, are the use of 72 pixels can be, and with the development of the industry, more and more high-score screen technology, but also make the mobile phone and other mobile devices the screen resolution gradually rise. For outdoor advertising that needs to be viewed from a distance, the resolution does not need to be set too high, as long as the clarity of the picture is guaranteed. In general, we should not generalize according to the resolution that different projects are suitable for now.
When handing over the source file of the design manuscript to the pre-press staff, it is necessary to ensure that all fonts in the file are converted into curves (vector mode), because there are many types of fonts, there is no corresponding font in the producer's computer, in order to ensure the unity between the design file and the final product, it will not destroy the aesthetics of the original design because of the lack of fonts, and make sure that all the text is vector processed (turning curve) before handing over. The figure above is one of the methods that introduce PS and AI software to turn text into curves.
In software such as Adobe Illustrator and InDesign, in order to avoid the file size caused by too many pictures, the pictures dragged into the software interface are presented in the form of links in the interface by default. When handing over a file with the producer, we need to make sure that all the photos in the file are embedded, or we can provide the original file of the internal picture. In order to avoid the situation that the image is missing because it is not embedded and there is no replacement file.
It is said that the finished product color difference printed by RGB mode will be relatively large, when designing prints, it is necessary to use CMYK's printing color for design, if the previous use of RGB, you need to convert the color mode in the image menu, here you need to pay attention to, after converting the color mode, check the degree of change before and after the color, and readjust the undesirable color. Some of the picture browsing software in the computer is for RGB mode, when viewing cmyk mode images, most of them will appear color overexposure, which is a normal phenomenon and will not have any impact on the actual printing effect.
Versions of the software are usually backward compatible, and when designing the articulation, we need to save the file in our hand as a version that the producer can open. In addition, when stored from a higher version to a particularly low version, it may result in some features being invalidated or incompatible. In this case, it is also a good idea to save the footage as a PDF or a printable JPG file.
For text that needs to be read carefully, we need to avoid processing it in spreads, and the spread mentioned here is the formal practice of linking the left and right pages across the position of the seam in the book. Spreading text often results in dyslexia, especially smaller text. Unless it is necessary to express special artistic effects, decorative text may be processed in a graphical way. In general, it is not advisable to spread the body text.
When setting up the cross-page arrangement of the picture, you need to pay attention to the position of the middle slit not to cut to the face of the character, because this will give people the impression that the head is cut, especially when dealing with photos of corporate leaders. The image on the left is an example of a photo spread, where the face of the character becomes illegible due to the distortion of the seams in the book, and the picture on the right is modified to position the character to avoid the middle slit. Overall, it seems to be more natural than before the revision.
The image above is an example of a multi-person photo spread arrangement, because it avoids the face of the character being squeezed and cropped by the middle seam, and the overall connection is more natural and smooth. If you're someone in a group photo, you don't want your face to be cut or squeezed into the middle seam
But the laws of design are not static, and we need to make judgments based on the actual situation. The picture above is Adidas's brochure, in order to show the creative effect of the character's arm extension movement as the page is turned, the character is arranged in the position of the seam in the book to achieve the purpose of vertical mirroring on both sides of the character.
For multi-page books and albums, because of the number of pages and the way of binding, resulting in when turning the page, a part of the inner edge of the page will fall into the staple, in this case, if you add a cross-page photo, how should you ensure the integrity of the picture? The red position in the image above is the common area of the left and right pages, and the picture trapped in the book is pulled out by repeating the content of the picture, so that visually it looks like the two pairs of pages are perfectly stitched together.
In this issue, we learned about printing colors, learned about plate making and the working principle of various printing technologies, and we also learned about different papers and commonly used special processes. Finally, we shared some tips in prepress processing. I hope that this knowledge can help you, designers not only need to master printing knowledge, but also to understand different printing processes, understand these can sublimate the designer's ability to conceive, give printed products different texture and temperament attributes. I hope you can use the content of this issue flexibly, we will see you in the next issue!