The exact definition of printing is sometimes disputed, as it could be said printing dates back thousands of years. However, printing in its modern form is commonly said to be ancestrally linked to an invention by Johannes Gutenberg in 1435, in German. He used a wooden type printing machine for printing 30 copies of the Bible on vellum (made from calf leather).
The origin of metal prints
In the 1730s, William Caslon created a metal type printing machine. Compared to wooden types, metal types were very durable and considered a milestone in printing. A major drawback of these machines was that they were very time-consuming.
The compositor had to fix the individual metal types on the composing stick one by one. Words were separated using dummy metal types. Lines were separated by inserting metal strips between the lines.
Letterpress printing is perhaps the oldest method of printing. In this method, the letters and images to be printed are projected out of the so-called “relief plate”. Letters and images are embossed on the relief plate in metal print.
After that, hot metal types were introduced. In this new technology, the compositor sat before a keyboard and simply typed the text. Every keystroke sent a coded message to create type on the fly using molted metal.
In the early days, linotype machines were used (in which molten metal is poured when a complete line of text is typed), and then followed monotype machines (in which molten metal is poured when a single character is typed). The benefit of monotype machines was that the compositor could make corrections quickly.
Metal photo prints
In order to print photographs, half-tone blocks were invented for metal photo prints. A half-tone block is a metal plate on which a pattern of embossed dots is created. When pressed on an ink pad, these dots get inked, and when this block is pressed on paper, the photograph is printed on paper.
Nowadays, lithography and offset printers are used to print a large number of copies in a short time with high-quality printouts.
In lithography, the letters and images to be printed are at the same level as the plate. Oil and water repel each other. The plate (if the printout is multicolored) used in litho printing is created using the printout you take on the laser printer or imagesetter.
The letters and images are printed on the plate. When this plate is brought into contact with ink and water, the oily ink sticks to the printed portion of the plate and water sticks to the unprinted portion. Since the oily ink and water repel each other, the ink doesn’t spread on the unprinted portion of the plate.
Offset printing
Offset printing is generally used to undertake litho printing. The plate is wound over the plate cylinder. The inking roller and dampening roller continuously ink and dampen the plate wound on the plate cylinder.
The letters and the images are transferred to the rubber-coated blanket roller. Finally, the letters and images on the blanket roller are transferred to the paper that passes over the impression cylinder.
Creating the prints
During offset printing, there are two different types of printing presses that might be used. Sheetfed presses are a type of printing that uses individual sheets that are manually fed through the presses.
Web presses are a type of printing that uses large rolls of paper that are then cut into the appropriate size during the finishing processes. Web presses are usually reserved for large printing jobs, whereas sheetfed presses can be used on shorter runs.
Regardless of the type of press that is used, the printing process remains the same. Ink is applied to the metal plates that were created, and then the paper is loaded.
The metal plates will transfer the ink to the paper during the printing process, and then the procedure is repeated for each of the four colors, creating your full-color project.
Finishing the job
The finishing process involves everything that has to occur to your product after printing and before it is delivered to you. This includes being cut into the appropriate sizes, being bound, or being folded.
For instance, business cards are usually printed in a large sheet and then need to be cut down to the appropriate size. Booklets need to be bound before they are completed, and brochures need to be folded.
Most of the time, this part of the printing process will be done by machine. Your printer likely has a machine that can cut through hundreds of sheets of paper at once, as well as one designed to automatically fold papers.
This allows them to complete those parts of the process quickly and efficiently. Binding can take more time, ranging on the type of binding utilized. Binding options include stapling, stitching, and gluing, depending on the project at hand.