Printing Glossary

Raster Image

An image made up of entirely pixels. The alternate method would be an entirely vector image; made up of only shapes that are mathematically filled.

Raster Image Processor (RIP)

A device that translates data into dots or pixels.


To render an image, pixel by pixel, vertically and horizontally.


The number of dots or pixels of an image. The higher concentration of dots or pixels per inch, the more detailed the image will be. Most printers requires a DPI/PPI of 300 or above.

Reader's Spreads:

Multi-page documents made into two page sections, so they are in the correct sequence for reading, as compared to Printer's Spreads. Reader's Spreads need to be rebuilt before going on press to be Printer's Spreads on the final press sheet.


Amount of detail of an image on film, paper, computer screen, or disc. In digital prepress resolution is usually measured in Dots-Per-Inch (DPI).


Type, graphic or illustration reproduced by printing ink around its outline, thus allowing the underlying color or paper to show through and form the image. The image 'reverses out' of the ink color. Also called knockout and liftout. In the case of process printing, this usually refers to white type defined by the surrounding printed color.

Red, Green, & Blue

These are most commonly used with television screens and computer monitors but are not used in offset printing. RGB files need to be converted to CMYK for printing. Colors may need to be adjusted after the conversion and may not appear correctly on your monitor.


Abbreviation for red, green, blue, the additive color primaries.

Rich Black

This is made by mixing colors of ink with black in order to produce a deep, dark black on press. To create rich black for full-color process printing, your CMYK values typically should be Cyan: 60%, Magenta: 40%, Yellow: 40%, Black: 100%