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).

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 to 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. 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 early days, linotype machines were used (in which molten metal is poured when a complete line of text is typed), and then followed mono type machines (in which molten metal is poured when a single character is typed). The benefit of mono type machines was that the compositor could make corrections quickly. See here EMBOSSING ROLLER https://www.embossingroller.com/


In order to print photographs, half-tone blocks were invented. 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 amount of copies in a short time with high quality printouts.

In lithography, the letters and image 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 image setter. 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.