On the most popular security printing technology

2022-07-31
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On the anti-counterfeiting technology of bill and Securities printing (Part 2)

v. identification of the authenticity of valuable bills and certificates

when we hold a valuable printed matter, such as checks, certificates, banknotes, invoices, etc., once it is identified as a counterfeit, the rights and interests of the holder will be damaged immediately. Among the numerous medical plastic exhibits, we should have a certain knowledge of identifying the authenticity of tickets (coupons), so as to take timely measures to safeguard their rights and interests

(I) identification of paper

paper is mainly composed of plant fibers and auxiliary materials, which are specially treated by Gabor. Its main physical properties are: durability, tear resistance, fire resistance, smooth surface, easy to write, and a sense of value. Therefore, it can be identified from the following aspects:

1 Whether the anti-counterfeiting paper has a watermark or the depth of the watermark. The authenticity can be identified by irradiating the light or comparing two identical tickets (coupons)

2. color and position of dark lines. There is no need to put dark lines on ordinary paper. Only special valuable ticket (coupon) paper has dark lines. There are many different colors, and there are single color or multi-color mixed in the production. If the position and color are consistent, it is the genuine. Of course, sometimes a slight difference is not a fake, but only an error in the production

3. structure of special fiber. According to the different characteristics of different tickets (vouchers), different fiber filaments are used in the production and their distribution is also different. Sometimes they are colored visible fiber filaments, and there are also invisible fiber filaments. Both of them can have fluorescent reflection under the irradiation of ultraviolet lamp. They have different colors and special structures, which are the key points of identification

4. thickness and evenness of paper. The thickness and evenness of the paper can be seen by light or light to see whether its distribution is uniform, or by hand

(II) ink identification

ink identification is a professional method, which is not easy for ordinary people to identify

ink is made by mixing and grinding pigments and some additives, so it can be distinguished from the following methods:

1. color and luster: carefully observe whether the color of the printed matter is correct, bright and shiny

2. texture: relief and intaglio prints often have strong texture and bright colors, and their surfaces can be directly touched by hands to feel convex and concave, while flat printing shows that the images are average and light

3. water resistance: according to different printing products, water-resistant inks can be selected. For example, in order to prevent water, alcohol and other liquids from tampering with the face, water exchange industry information soluble inks are used, making it difficult to achieve the purpose

4. lightfastness: poor quality inks often fade after exposure to strong ultraviolet and sunlight for a certain period of time

5. Abrasion resistance: according to different printing products, some printing inks with strong abrasion resistance are often used to prevent alteration

6. special ink:

① fluorescent ink: this ink shows fluorescence under the irradiation of UV lamp. It is also divided into colored and colorless fluorescent inks

② photorefractive ink: this kind of ink is colorless, easy to distinguish the authenticity, and difficult to copy. It only needs two seconds under the purple light or sunlight to develop color

(III) identification of printing methods

different printing methods show different characteristics, which also bring favorable conditions for identification. The following briefly introduces the characteristics of several common printing methods:

1. lithography: a common indirect printing method, which is characterized by average image lines, consistent image lines around, light image ink and thin ink layer, The color light change-over switch should be turned to the loading gear with low brightness

2. relief printing: it is a commonly used direct printing method, which is characterized by thick ink layer and strong gloss. When the print is observed with a magnifying glass, the lines and drawings are sunken around, the burrs are prominent, and the strokes are not neat

3. gravure printing: it is a special printing method, which is characterized by thick ink layer and strong gloss

source: printing world by fanshiyun

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