Definitions of Color Separation Photo Engraving The following terms are often used when talking about color separation technology used in photo engraving:
Four Plate Process: Modern color printing uses the four plate process for producing colored prints. Typically, the four colors are yellow, magenta, cyan, and black. During the printing and engraving process, the plates can be combined for different color combinations. While theoretically the three colored plates overlaid on each other would produce black, the black plate is used to offset the colors of the other three.
Masking: In engraving, masking is the process that blocks out either a positive or negative image on a plate that is used for engraving. This is done to help correct color problems.
Color plates: Metallic plates that are used for printing and engraving. They are usually etched with a negative image and then different inks and masks are added to the plate during printing. Because they are metal, these color plates will last for a long time.
Negative Image: In the photo engraving process, the negative image is the reverse of the positive image, or the one seen with the naked eye. Colors are filtered and masked on a negative image engraved on a plate, which can then be used for printing. Since the printing material will be in the reverse of the negative image, it recreates the original positive image.
Proofing: The time it takes the inks to dry between color plates in the printing press. If not enough time is used, the inks will be overlaid on one another while they are still wet, resulting in a sloppy image.