The most important printing process for high quality printed output is the process called "photo-offset lithography". This process is commonly called "offset printing" and would be accomplished through the use of an offset press. The plate in the offset process looks normal, since the image is printed onto a "blanket cylinder" and then the backwards image on the blanket cylinder is then transferred to the paper that is going through the press. That is where the name "offset" comes from, since the image is not printed directly to the paper. This process makes it much easier than working with backwards type as in the next process listed below.
"Letterpress" or "Relief" printing is probably the oldest printing process developed by man. The early process depended upon carved wood or cast metal letters assembled (backwards!) by hand. The process gets its name from a "relief map" which shows mountains or elevations. The raised part of the type containing the letter is inked and paper is set on top. pressure is applied and the ink is transferred to the paper surface. Many beginning artists have done simple relief printing using a carved linoleum block in an art class. Early books and newspapers had to have each page handset in order to be printed. The earliest book ever printed was printed by a gentleman named "Gutenberg" in Germany, and he is given credit for the development of movable type. The book recently sold at an auction for over one million dollars.
The "Gravure" (also called "engraving") process is another old printing process that relied upon methods of etching a metal surface. This etching would create cavities in the surface of the plate. The plate would be loaded with ink, and then wiped clean. However, some ink would remain in the cavities on the plate. When paper was placed on the plate, and extensive pressure applied, the paper would touch the ink in the cavities, and the image would be printed. This gave a raised look to the printing, and gravure printing is still utilized for printing items such as wedding invitations.
The "screen printing" process is probably the most versatile method of printing. This is because the process allows the printer to print a wide variety of surfaces, such as wood, metal, glass and cloth. The process is really only a simple stencil attached to a cloth stretched on a wooden frame. However, improvements in the process have led to the use of photographic techniques that require training and practice to become proficient. A thorough knowledge of inks and stencil compatibility are also required. Ink jet printing technology and embroidery have had an impact on the screen printing market, and its use is in decline as these newer technologies are developing.