Consumable inks in the printing industry are divided into two parts with general use and security. General inks are used in everyday use such as printing books, publications, promotional products and packaging. These compounds are produced based on water and various solvents and fixed using infrared, ultraviolet or hot air dryers. These compounds have stable and stable properties and their color is not subject to changing the angle of view, radiation and type of light and ambient temperature. This category of inks is formulated according to the type of printing system (letterpress, offset, flexo, screen, rotogravure), printing speed, printing mechanism (sheet or roll) and the application of the printed product (food, pharmaceutical, etc.) and each system has special features. have their own
Security inks are inks with special chemical and unusual physical properties that are often used in flexo, screen and intaglio printing systems and with special and exclusive formulations under the supervision of expert technical experts and with strict security controls and in general or by order of special printing houses. are produced Extensive research is always done in the production and improvement of these products in the chemical laboratories of manufacturing companies, and valid security guarantees are issued to consumers. Also, the specifications of some unique production products commissioned by security printing houses for printing banknotes and government securities will remain confidential with the manufacturers. The complex and unique features of these compounds and the exclusive and limited production by a few companies in the world have resulted in printed products that have high value or are used in the packaging of some special products. Take advantage of these compounds. It should not be overlooked that today many companies in this field are producing similar compounds. But the products of the giants in this field are still less similar in the world markets.
Getting to know the types of security compounds
a: Consumable compounds in the basic and preliminary compositions of the document(Primary Features)
Distortion of the texts of security documents It has been done for a long time by special solvents with incredible delicacy, so printing special graphic patterns using inks sensitive to various solvents in the background makes it possible as soon as the document is manipulated (with a variety of organic chemicals, inorganic and aqueous solvents) , bleaches, acids, etc.) to create obvious color reactions in its context. In such a way that the color of part of the graphic patterns changes or the document is completely distorted and has a large color stain.
It should be noted that if ordinary laser printers are used to insert specific variable information on the document, these security combinations should be used with special considerations.
Basic compounds in security documents are divided into three categories according to their reaction to solutions:
- Sensitive compounds against mineral and aqueous solvents
- Compounds sensitive to organic solvents
- Compounds sensitive to chemicals
This series of compounds, which are sometimes called varnishes, according to their chemical properties, are used by offset or screen systems on the entire surface or locally, or mostly to print a specific graphic pattern with high ability to sit on uneven and absorbent papers. .
B: Compounds used in the secondary compounds of the document(Secondary Features)
A printed security document consists of different parts. Combinations that each play a key role in its authenticity and ownership. After securing the background from threats caused by solvent attacks by counterfeiters, it is time to print the main compounds on the secondary layer. The composition of this layer should also have high security features to avoid any distortion. Features such as the ability to change color against light rays with different angles and types, color change due to temperature fluctuations, noticeable prominence, readability by special devices, etc. make a security document take on unusual and different characteristics from normal documents.
The safety quality created by these security compounds depends on factors such as the type of paper, specially designed graphic compounds, and special printing machines and finishing operations. Factors that access to each of them has many limitations. The types of inks used in the field of security printing are:
They are very high quality inks, with the help of their special properties, very delicate effects can be printed with exceptional quality. The color range of this composite series is very wide and can be ordered according to the needs and type of feeding of the printing machine (roll paper). Coldset, Heatset, UV inks, printing varnishes, Pantone inks, etc., are all types of normal inks.
Visible or Invisible Fluorescent
The textual and image effects printed by this compound are invisible in normal light (without color) and visible against the radiation of UV light rays.
IR Visible/ Invisible Inks
The above compound is one color in normal light and another color when exposed to long wavelength or infrared rays. This water base compound is fixed by UV drying. The visible colors of this compound are black, blue, red, orange, yellow and green and the invisible colors are yellow, green, orange and blue.
Metalic High Reflectancy UV Curable:
Using this compound with gold or silver color spectrums (using a UV dryer) is a form of safety defense against advanced color scanners and copiers that are abundant in the market. When scanning images or color texts printed by this ink or preparing a color copy, a dark image is obtained due to strong reflection of light. In a type of colorless metallic ink, the image printed on the background of the document is hidden from normal light, but after scanning or copying the document, the text or image appears, which indicates that it is a copy or fake.
Due to its colorless property and high ability to transmit light, after printing on 60 to 100 grams paper, it is used as a composite for producing quasi-watermark images on all types of normal paper. After printing the image or text on both sides with this ink and viewing the document under normal light, the printed image looks like a watermark effect inside the paper. The processing of this type of compound and the emergence of watermark effects requires increasing the temperature of the paper to 150 degrees Fahrenheit and reducing it to below 75 degrees Fahrenheit after printing with flexo and rotogravure techniques.
Metameric-Multi Interference color
Metameric composites have different colors when viewed in different lights due to their special properties. When the image printed using this ink is seen under standard light, one color appears and when viewed in a different light, another color appears. The technology used in the production of this composite series, which is called Pearlescent Pigment, is based on titanium dioxide and mica compounds. In terms of physiological structure, the pigments of this type of compound do not have any characteristics of harm to human health and environmental risk, and this compound can be used for food packaging and children’s toys. Also, pigments are insoluble in water and do not contain heavy metal compounds. There are many choices for the color spectrum of this type of compound, of which silver and gold are the most spectacular. Flexo, intaglio, screen and rotogravure printing systems are suitable for printing all kinds of UV compounds and the above solvent base.
A variety of inks that can be used in the Intalio printing system include the selected system of first-class security documents, which after printing the graphic design, effects such as a palpable bump appear and the possibility of engraving after printing (in order to engrave very fine patterns on provides the images and texts printed by this printing system to the printers. Also, by using this type of compound, one and three-dimensional hidden images or words can be placed inside the document, even in large dimensions. Intalio printing system is based on digital and manual engraving of images on the surface of the plate. Intalio compounds are based on water solubility and become waterproof after drying. Due to the shrinkage (shrinkage) of the image effects printed with this ink after drying, very precise and delicate images and texts can be created.
After the intaglio inks are completely fixed on the paper, they resist scratching and cutting, and the intaglio effects cannot be removed or erased without damaging the paper substrate. These compounds are highly resistant to the heat caused by laser printers, unlike thermography.
The change in color of this compound when exposed to heat, especially in contact with fingers, is one of its distinguishing signs. This compound changes color as soon as the temperature increases and returns to its original state after decreasing. The simple and accessible method of testing the authenticity of thermal compounds has made it very important. The type of color and the thermal range of color change of thermochromic compounds are different according to different models of the manufacturer. The use of thermochromic compounds on surfaces such as polyester, PVC and plastic is also possible, and due to the structure of the ingredients, it is unimpeded in the packaging of food, drinks, labels and children’s toys. Suitable printing systems for this compound are flexo, rotogravure and screen. When these inks are used in combination with other designs printed by other colored inks, an effect like a rainbow appears after the surface is heated.
The amazing color change of this type of compound is different against different light rays. Observing the magical color change in all types of this composite series is unique to a specific range of wavelengths and it is possible to print it on different surfaces.
In a compound called LightTeil, color changes occur in the 300-410 nm range. The color of this type of composite is subject to the radiation of special lights and does not become fixed and permanent. The technique used to print it is screen and flexo.
Magnetic or MICR
The reading of certain specifications of the documents in order to accurately control them, which has always been considered as one of the bottlenecks in the workflow and time-consuming in the logistics and storage of securities, has been solved today by smart electronic systems or electromagnetic readers. The use of different code models and embossed or laser toner printing systems using solvent-based inks and water and special and non-distorting magnetic toners, as well as the use of readers with many advantages over OCR systems in document coding, while improving the safety factor. And the speed of control of securities minimizes the possibility of any forgery and manipulation. Magnetic ink and toner can even be printed and hidden or read under offset inks or without removing the document cover, which minimizes distortion and maximizes control speed.
Toners or magnetic compounds are used in two combinations: In the first combination, the magnetic code or image is fixed in all documents. But in the second combination, each document has a unique magnetic code, which is printed by electromechanical letterpress enumerators or digital printers using magnetic toners. Ink and magnetic toners can be used to print hidden smart patterns.
OVI compounds have a dual color nature due to their special chemical structure. Patterns printed with this ink show the first color when viewed directly, and the second color when the viewing angle changes by 45 degrees.
Color copies prepared from documents printed with OVI inks do not have these color changes in the desired graphic effects. Even very accurate digital scanners cannot record this color change.
Coin contact reactive compounds (Coin Reactive)
Compounds sensitive to the contact of the coin are revealed after being exposed to the movement of the edges of the coin with the printed surface and applying specific chemical reactions. This image is hidden before coin contact and cannot be seen. One of the advantages of this method is easy access by identifying the authenticity and visibility of the coin.
Compounds for scoring With letterpress numerators (Bleed Through – Secure Numbering)
The scoring security inks are visible from the back of the paper after printing by raised mechanical or electromechanical metallic numerals. The color of this type of ink can be seen from the back of the paper in the same color or in a different color after penetrating the inner tissue of the paper. This feature thwarts counterfeiters who rely on digital printers or numerators and normal compounds.
Solvent based scratchable compounds (Scratch Off Solvent Base)
Scratch-off inks with a solvent base and very high opacity against the passage of light are used to temporarily cover the surface of some information already inserted on the documents. A layer of this compound hides them under it by being placed on a strip of codes or special messages. After drying, this compound layer can be easily scratched or removed by a nail or a surface. The printing system of such compounds, which are produced in metallic color spectrum (silver, gold, copper) and many other special colors, is screen, flexo and rotogravure. It is possible to print scratch-off inks in several layers on top of each other, and it is recommended to use a layer of UV varnish under all layers.
Water-based scratchable compounds (Scratch Off Water Base)
With almost the same user characteristics as the solvent-based type, but with the difference that the scratchability of this compound is much softer and easier than the solvent-based type. This compound is produced with a wide color spectrum and very high turbidity against the passage of light and a pH between 2.7 and 5.7 and a very long life.
Visible and invisible compounds at short wavelength (Visible or Invisible Short Wavelength)
Short wavelength compounds are formulated in varnish or pigment of other security compounds and produce a night-like glow with a wavelength of 254 nm. The structure of this type of compound is produced in solvent, blue and UV bases and is printed by flexo, rotogravure or screen printing systems.
Fluorescent glow blocking compound (Fluorescent Block)
Compounds without color and special coating to block the brightness of fluorescent effects caused by visible and invisible inks and are available in blue base, solvent base and base formulas.
Due to the very high ability of the ink to absorb infrared and ultraviolet rays, its cover varnish is completely transparent (against the passage of light) and it can be used on other inks (without affecting the final color) using flexo techniques. , enables rotogravure, screen and intaglio.
Ink for the signature space (Remove All Signature Panel)
Inks with mechanical sensitivity against manipulation and distortion are often used to print signature space on credit cards.
The unique effects of special phosphorescent pigments in the composition of this compound make it visible in a range of ultraviolet or infrared light. Copiers and scanners are unable to capture the effects produced by this compound.
Invisible varnishes are transparent coatings and appear colorless under normal light. This product is available in matte, glossy and semi-gloss models, water-based, solvent-based, and UV-based, and yellow, green, blue, and orange colors. Detection of pigment is only possible after exposure to high wavelength UV light (366 nm) or short wavelength UV light (254 nm) in the dark. This varnish is transferred on paper in the form of cylinder, flexo, rotogravure or screen, and after opening the can, it has a lifespan of nearly one year provided it is kept at a temperature of 68 to 72 degrees Fahrenheit.
The structure of the pigments that make up this compound has made a unique feature for it. Color change based on the angle of light radiation is its main nature and this feature is not transferred in case of scanning or copying of the document printed with this ink. Flexo, intaglio, screen and rotogravure printing systems are suitable for printing all types of UV compounds, solvent base, oil base. The colors of these compounds are different and can be ordered.
Solvent-based compounds are screens that change from visible yellow, green, blue, purple or red colors to another color due to infrared radiation (785-910 nm). There are various types of this compound that can be used in all printing systems.
IR to IR
There are invisible compounds that require type 3B laser waves to be activated. The range of infrared wavelength effective on this composition is 900-800 nm, and in this range, color changes and extraordinary shine. The lifespan of IR to IR composite is more than 50 years. Different models of this compound type can be used with all printing systems.
IR to Visible
There are invisible compounds that need a 3B type laser with wavelength ranges of 940 to 980 nm to glow.
After exposure to the radiation of this wavelength, green, red, blue, and yellow spectra appear and this light reaction has a continuity of more than 100 years.
Compounds sensitive to changes PH
These security compounds change color against acidic and alkaline factors and reveal the distortion of the document. The printing of these compositions is done by flexo and rotogravure systems, its color variation is in 23 spectrums and transparent.
Invisible composites sensitive to change PH
The reaction of alkaline and acidic substances on this compound will be determined only against the long wavelength of ultraviolet. The application of this compound is in security documents, whose contents should remain imperceptibly protected from distortion for many years. In these documents, as soon as the document is manipulated by acidic and alkaline solutions, the distorted part shines in a certain color against a specific wavelength of ultraviolet waves without damaging other parts or being obvious under normal light.
The production of this type of compound is in the form of water-based UV varnishes and is done by flexo, screen or rotogravure systems. Choosing the visible color spectrum of this compound against special light is green, yellow or blue.
Compounds with micron detection capabilities
They are transparent varnishes based on water, UV or solvent, in which very small particles of variable size (15-30 nm) are suspended. These colored particles are often not visible to the naked eye and a microscope is used to track and see them. Also, the color of these particles can be ordered based on the customer’s needs.