A list of substrate issues to be considered in the

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A list of substrate issues to be considered in prepress design (I)

when talking about substrates, everyone coincidentally thought of paper, but in fact, substrates are far more than paper. This paper mainly introduces substrates from the perspective of prepress design

first, paper

wood pulp paper is not as old as we thought. The papermaking process using wood as raw material did not become popular until the 1980s. Before that, the raw material of papermaking was mainly rags. It is said that the inspiration for human beings to use wood pulp as raw material for papermaking comes from the process of wasps building nests with chewed wood pulp. Of course, this is just a legend, there is no exact textual research

in any case, nowadays, the vast majority of substrates are still paper materials, and paper materials alone also contain various categories. In prepress design, the characteristics of paper substrate must be fully considered, otherwise even if the designer's work is creative, it is useless. The following will introduce in detail some characteristics of the paper substrate that the prepress designer must consider

1. Paper classification

the first thing to consider is the most basic paper classification. Paper is generally divided into securities paper (advanced writing paper), books and periodicals paper, glossy paper, coated paper, cover paper, paperboard, account book paper, paper, offset paper, scallion paper, label paper, selenium electrostatic copy paper, etc. Securities paper (advanced writing paper) is mainly used for printing special stationery and securities. Selenium xerographic paper is the basic paper for printers or copiers, which is what we call "white paper or plain paper". Of course, different paper mills have different names for this. Glossy paper is widely used for card or postcard printing. Paper is a kind of paper made of crushed wood pulp, which is cheap and mainly used in newspapers. Of course, cover paper can be used to print covers. In addition, it can also be used to print other wear-resistant prints that need a certain thickness. In fact, with the development of the paper industry today, there have been many paper classifications and related applications. Designers should consider these issues in practical work

the first step in selecting live paper is to determine the type of paper used. Obviously, if the printed live parts are special stationery, there is no need to use cover paper, because the special stationery printed with cover paper will make customers pay additional mailing fees due to the increase of mail weight. But when designing the cover of a paperback book, the designer will definitely think of using cover paper, because this kind of paper is stronger than other high thickness paper. However, when printing promotional postcards, designers will consider using high-thickness paper, such as glossy paper, because this kind of card can withstand the processing of post office manual equipment. If the card is broken before it is sent, the card promotion will lose its meaning. If the promotional object receives this card, the consequences are unimaginable. In fact, the post office has regulations on the thickness of mailing materials, so we must pay attention to the relevant regulations of the post office when selecting paper

2. Basic weight of paper

even for similar papers, there are basic weights. The so-called basic weight comes from the thickness of a certain type of paper. For example, the securities paper and cover paper we usually contact have different thicknesses. Generally speaking, the basic weight of paper is the weight calculated in pounds after a certain grade of one ream paper (500 sheets) is cut into the basic size, which is the specific calculation method of the basic weight. For example, the basic size of an ordinary 20 pound security paper is 17 × 22 inches, which means 500 sheets 17 × The 22 inch bond paper weighs 20 pounds; 500 sheets 17 × A 22 inch 50 pound bond paper weighs 50 pounds, and so on

although most colored printing papers stipulate the basic use weight, the thickness of cover paper is often measured by "points", which is different from the "points" used in typesetting. The number of points used in the paper industry is equivalent to one thousandth of an inch (0.001), so the thickness of the cover paper at 10 points is 0.01 inch; The 20 o'clock cover paper is 0.02 inch, and so on

why is the basic weight of paper so important? There are many reasons. First of all, the thickness of paper will affect the printing effect and quality of printed matter. Whether the selected paper is too thin or too thin, there will be problems when printing. For example, mailing materials need to be wrapped, which requires that the paper used has a certain thickness without appearing too thin or too thick, otherwise a large mailing fee will be paid

when printing marketing materials, product promotional materials, entrainment materials, or image promotional materials, you must always remember this: if these materials need to be mailed, especially when mailed overseas, you need to choose postage economical printing materials. If the customer finds that the paper he uses makes him have to pay an extra postage, he may not consider you the next time there is a similar business

also need to consider the folding of printed matter. The thicker the paper used, the more difficult it is to fold, especially when using automatic folding equipment, this problem can not be ignored. The greater the folding difficulty, the more serious the damage of the printed matter will be

of course, the designer does not have to remember the basic weight of all papers, and can carry the basic weight table at any time. When determining the paper that should be selected, you can refer to the samples provided by the printer or paper mill. This is the best way to determine the problem of paper selection

3. Surface finish of paper

when determining the selected paper, the surface finish of the paper also needs to be considered. The requirements of paper surface for printing live parts depend on their end use. According to the surface finish of paper, it can be divided into high gloss surface paper, unsmooth surface paper, surface coated paper, textured paper and calendered paper. The surface coating paper includes single-sided coating (C1s) and double-sided coating (C2S). Therefore, when printing special stationery, we should consider that the surface finish of the paper should be suitable for pen writing, and we should not use some textured surface paper with high decorative degree, otherwise the signature on the stationery will look like that written by a drunk

in addition, it should be noted that many special stationery are used for laser printers or other office equipment. These stationery should not be too thin, otherwise they are not suitable for these office equipment. Similarly, this aspect should also be considered when printing envelopes, because envelopes of many units need to print the address and name of the addressee on them through printers, and these envelopes also need to be charged through the postage meter of the post office. It seems that these problems don't need to be considered, but I still remember that the staff working in the post office often reflect that those envelopes with wide and high surface finish are used (in fact, those envelopes use synthetic paper, which is lighter than ordinary paper, and the price is very low.) When charging on the postage meter, the ink on the meter never dried well on the envelope. As a result, the postage stamp was erased after the envelopes were piled together

an important problem about the surface finish of paper is the ink repellency of paper (its opposite is ink absorption). Ink repellency refers to the extent to which the paper does not absorb (repel) ink. The degree of attention to this issue depends on the printing method and content. If many of the printed contents are pure colors (for example, the color of the whole paper is black, etc.), more consideration should be given to the ink adsorption of the paper, otherwise it will take a long time for the ink on the paper to dry, and it may even be impossible to wait for the ink to dry and continue the next process

what's more serious is that if a living part involves glazing, film coating, folding or other subsequent processes, and these processes are part of the online printing of the printing machine, and the ink is not dry, the adhesion of the coating after glazing will not meet the design requirements, and the print will be dirty when the printing equipment is running; Or the printing parts have to be taken off the production line midway until the ink dries before post press processing. The cost of doing so will be very high. Not only will the printing chamber ask for additional fees, but also the construction period may be approaching and the grace time cannot be won. Even after the ink is dried, it is useless for the printer to return the live parts to the production line, so the losses caused can no longer be compensated

on the other hand, it is not good for paper to have too high ink absorption. For example, when using porous paper as substrate paper, the printing color (black is no exception) will appear dim due to excessive ink absorption of the paper. We know that when the ink-jet printer prints with ordinary paper, the ink will be adsorbed to the paper too much, and the color on the printing paper is not as bright as that displayed when printing with special ink-jet printing paper. People who use inkjet printers may have experienced creases and wrinkles when printing with damp paper, which is the result of the interaction between high ink absorption paper and high flow ink. Even traditional printing inks may have such problems, because different ink dynamometers are classified according to the largest force value applicable to the structure and sample of a UTM experimental machine, and their fluidity is different

improper consideration of ink absorption of paper not only affects the beauty of printed matter, but also has the problem of ink perspective, that is, words or images printed on one side penetrate into the other side. This is really a bad thing. For example, in the process of magazine printing, the advertisements of a manufacturer penetrate into the advertising pages of its competitors on the other side

this problem is also related to the ink used by printers. Different printing machines have different requirements for ink. For example, the types of inks used by web wheel transfer printing machines, heat setting web printing machines and small sheet fed printing machines are different, mainly due to different drying methods. Therefore, it is necessary to ensure that the paper, design and ink used for printing live parts are compatible. In addition, the performance of color ink and spot color ink is also very different, so you must be careful when choosing

4. Paper opacity

the discussion of ink repellency and ink absorption of paper leads to the topic of paper opacity. The so-called opacity is the difficulty of viewing the other side from one side of the paper. When printing spot color, thick lines or titles on both sides, the requirements for paper opacity should be more strict

above 10. Cleaning the mixer at the end of the work is some issues to be considered when selecting paper. Choosing paper is a very complicated work, not only to consider all the problems mentioned above, but also more. Paper is a very complex printing material. None of its characteristics exists independently of other characteristics. When studying the characteristics of paper, we should consider comprehensively, and never favor one over the other

for this problem, here is a suggestion, that is, when selecting paper, we should cooperate with printers to jointly decide the type of paper to be used, and both sides should solve this problem before the design of printing parts begins. We often hear printers complain that the things designed by some young designers with "empty eyes" can't be printed at all, and sometimes they can't find the paper suitable for the design requirements at all. This gap between the two sides is easy to cause serious consequences, especially when China has become the country with the most developed online shopping, web printing

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