Justin is my old boyfriend in New Orleans who teaches printing in a trade school. He is the one who taught me enough printing to get a job - he used to have his own print shop. I learned typesetting, camera, and binding, but not running a press, because I don't like to get my hands dirty. Pressmen's hands are always stained with ink, like mechanic's hands are always stained with grease. I don't mind getting my hands dirty once in a while, but not all the time.
The computer has changed the newspaper world, all type is set on computer these days, although newspaper are still printed from plates. The process is usually photolithography. A litho plate is metal coated with an emulsion that hardens when it is exposed to a very bright light like an arc lamp. The film is black and clear, no grey. When the plate is exposed, the part that was clear lets the light through, and the emulsion hardens. The emulsion that wasn't hit by light stays soft. Then you wash off the emulsion, or dissolve it off with a special solvent. Then you rub the plate with a gum to protect it.
When the plate is put on the press it is flexible, and bends into an arc to fit the cylinder on the press. The ink sticks to the emulsion, and is offset, that is, it makes an inky reverse impression on a rubber roller, and that inky reverse impression is what touches the paper and makes a positive ink mark on the paper. The process uses water, too, which sticks to the part of the plate and roller that isn't inky, and keeps the ink from adhering to the non-image area. |
