Since time immemorial, mankind has experimented with a variety of techniques to reproduce symbols and graphics, each time in a simpler, faster and more efficient way. In this search, the need for massive and realistic reproduction began to be noticed, seeing automation and improvement in terms of pigments, so that they were simple drawings… This is how printing techniques were born!
As in all beginnings, manual work was predominant. However, with the passing of the centuries and the technological changes in humanity, product of the innate curiosity of the human being, Johannes Gutenberg became the father of modern printing. Surely he never imagined that his invention would reach 3D printing and surely it will continue to evolve!
Even at the level of materials, printing techniques have diversified because innovation and human creativity have no limits, reinventing the concept of printing, but always maintaining the fundamental principle of it. Join us on this journey from the oldest to the most recent printing techniques.
THE FIRST PRINTING TECHNIQUES
According to historical data, woodcut is the oldest known printing technique. This technique consists of making incisions on a wooden tablet using a pointed tool, which allows to shape reliefs. The piece was then dipped in wood ink, and after being submerged, it was pressed on a cloth or paper support to reproduce the image that had been carved.
This type of reproduction laid the foundations of fountain printing used to print books in their entirety, therefore, it is the technique that precedes the one patented by Gutenberg with the creation of the printing press in the second half of the 15th century.
Although it has fallen into disuse, the art has not let it die, although it has been improved by using linoleum and Adigraf, and calling it “linocut” or “linocut” or “linocut”.
Intaglio is another of the oldest printing techniques, although more considered as an engraving technique, although more specialized in illustrations, unlike woodcut. Another aspect that differentiates it is that it works in positive, that is to say that the elements to be reproduced are engraved directly on the matrix.
To explain it better, we have an engraving made in metal, in which the ink is distributed in the different incisions of the relief, to then exert pressure with a press and thus transfer the image to the sheet. As you will notice, this technique was also handled manually.
This was a printing technique similar to intaglio, only, used in an indirect way, since its principle was the use of chemicals to etch the relief previously made on the metal plate. In this case, the metal plate was covered with chemicals to then extract with a needle the substance according to the relief to be printed, which would be etched with acid.
Rotogravure advanced in intaglio, based on a rotary machine that worked with engraved cylinders. It became a photomechanical technique, as the ink was transmitted through micro cells with different depths. To achieve variations in tones, a greater or lesser amount of ink was applied: the lesser the amount, the fainter it was, the darker the print, and the more ink there was, the darker the print.
In the 1950s, printing techniques based on relief plates began to be developed. In this case, the process involved a plastic substance and ultraviolet radiation, which, when in contact, caused the liquid to harden.
The plates could be made in a short time, which favored newspaper printing at the time. However, the time factor was improved in the 1970s when faster drying soluble substances began to be used, which favored mounting on the plates.
Screen printing is a very popular printing technique since its implementation because it is compatible with various materials and industrial objects, such as: plastic, paper, metal and even three-dimensional surfaces.
The plates used, also called screens, are created by photomechanics and come into contact with a synthetic fabric or mesh coated with a photopolymer. After the procedure performed on a frame, they are exposed to a film positive and hardening takes place in the areas that will not be printed.
While the exposed areas are washed, generating open areas. Then ink is applied with a roller on these areas, putting it in contact with the surface to be printed and Voila! Serigraphy ready. This technique is popular in the printing of T-shirts and signs, even on large surfaces. It is also compatible with the use of various colors.
This is a technique that dates back to 1890, although it became more popular in 1952, when it was given its name. It was also based on the use of plates and the use of aniline colored inks, which, when diluted in alcohol, could be absorbed by non-porous surfaces.
Contrary to what you may think, this printing technique is not dead. It is currently used in packaging printing, specifically on packaging. For its massive use and the creation of several units, rubber is used in the plates, material that is placed over the single printing roller, allowing the possibility of creating copies.
It is a direct printing system based on the use of rotating cylinders. Unlike flexography, the areas to be printed look like low relief engravings, which are inked on the inside. For the use of colors, there are several rotary cylinders, each one with a different pigment, so that when they come into contact with the surface they are printed under pressure.
THE MOST POPULAR PRINTING TECHNIQUES
The principle of lithography is the chemical reaction between water and color, but also that the white areas and the areas to be printed are at the same level. Porous limestone is also involved in the process.
It is drawn on using a grease pencil and then dipped in water. The sections that have not been passed over with the pencil absorb a minimum of water, while the marked sections do repel water, which is why they are vulnerable to absorbing ink and when pressed against the press, the ink can be transferred to the paper. Color lithography is similar, but still has its variations.
This is one of the best known and most widely used printing techniques , especially when it comes to large print runs. The method works with cylinders and rolls, therefore, it is a type of indirect printing, in which the image is transferred from the lithographic surface to the paper or plastic. To achieve this, a rubber surface or blanket is used, while the plate is moistened with water and then ink is applied, thus obtaining the final result,
Offset printing derived from lithography, changing the use of stone for a metallized plate, on which images and graphics are reproduced. Given the practicality of this method, today offset printing is the system par excellence to achieve large print runs.
Modern offset lithography
We reached the improved version of both techniques (lithography and offset), in which the stone surfaces were changed to plastic plates, stainless steel and aluminum, which allows savings in terms of production.
The plates are coated with photosensitive material. When they come into contact with intense light, they undergo a soluble reaction, giving the possibility of transferring an image to a film positive or negative, so that they are printed on the surface of the plate
This is a widely used and improved printing technique , achieving excellent results in magazines, newspapers, packaging products, brochures, newsletters and other copies.
THE MOST INNOVATIVE PRINTING TECHNIQUES
ELECTRONIC PRINTING PROCESSES
The implementation of electronic printing opened up the possibility of making processes much more agile and saving on production costs and maintenance of large machines. Although the results can be better, there is a limitation and that is the number of copies that can be achieved by not having large sets of plates.
With the use of computers in the 80’s, printing became much easier, since the common user had the possibility of storing and editing files to be printed as many times as he wanted, changing printing techniques to a great extent.
Digital or electrophotographic printing
With laser printers a new printing technique was implemented, because the image quality is a spectacle! The only disadvantage is that it is a slow process, especially when you want to work with a large scale image.
The operation uses a base surface, like most techniques, although in this case it is used in a substance such as selenium or cadmium (photoconductive) that when in a dark environment generate static electricity and act as an insulator, so that when the laser is present, they lose their charge and enable the activation of the toner that will be printed on plastic or paper.
Ink jet printing
In this case, the printers used base their operation on ink injectors, being able to print images quickly and in high quality. As they are more advanced, they work in parallel to a computer from which the printing instructions or parameters are programmed. You have surely used it!
For this type of printing a special paper is required, characterized by the presence of millions of microscopic capsules, loaded with liquid dyes inside.
When an image is exposed to intense light, these particles are activated, hardening the ink inside. To complete the process, steel rollers press the image we have placed against another paper that acts as a support and where the dyes were reproduced, but not hardened, therefore, it is characterized by having quite vivid, sharp, bright and high quality colors.
THERMAL SUBLIMATION PRINTING AND WAX TRANSFER PRINTING
Sublimation, or sublimation, is undoubtedly one of the most popular printing techniques, although so recent in its implementation, even so, it falls into this type of techniques based on thermal sensation. In this case, heat is required to make the transfer of ink to materials such as paper, plastic or canvas. The process itself is slow, since it is necessary to apply one color at a time, using a tape that works as a color panel.
This printing and stamping technique called stamping can be Hot Stamping and Cold Stamping. It consists of transferring an image with the help of a metal support subjected to heat or high temperatures. As it is a heat transfer method, it is compatible with both old and new machines, but only for small print runs.
This printing or stamping technique is similar to the previous one, especially in the handling of a foil, the difference is that it is based on the handling of thermoplastic materials, which act in the presence of cold or low temperatures.
In this case we talk about a plastic or metallic base, coated with a photosensitive emulsion, where the image is engraved by a chemical process, forming a gravure, this plate is covered with ink and swept by a blade. Subsequently, a silicone buffer presses on the engraving plate collecting the gravure ink and transporting it on the piece to be printed by contact.
3D printing is the newest in printing techniques. It consists of a group of printers by addition able to give depth to an object making it three-dimensional, this thanks to the fact that it can print in sequence of layers in overlapping.
With this type of printing it is possible to go from a digital image to the materialization of physical objects. 3D printers have a technology capable of superimposing the exact number of layers to achieve the perfect and real replica of a flat image.
The process starts with a specialized printing software, programmed to generate sheets or thin layers, which will be moving on a base and work in plastic, until the three-dimensional figure is achieved.