A raster image processor (RIP) is a component used in a printing system which produces a bitmap. The bitmap is then sent to a printing device for output. The input may be a page description in a high-level page description language such as PostScript, Portable Document Format or another bitmap of higher or lower resolution than the output device. In the latter case, the RIP applies either smoothing or interpolation algorithms to the input bitmap to generate the output bitmap.

Originally (1980s) RIPs were a rack of electronic hardware which received the page description via some interface (eg RS232) and generated a "hardware bitmap output" which was used to enable or disable each pixel on a real-time output device such as an optical film scanner.

Nowadays, a RIP can be implemented either as a software component of an operating system or as a firmware program executed on a microprocessor inside a printer. Ghostscript and GhostPCL are examples of software RIPs. Every PostScript printer contains a RIP in its firmware.

See also raster graphics and vector graphics.