Raster image processor
Encyclopedia
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
system which produces a raster
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...
image also known as a bitmap
Bitmap
In computer graphics, a bitmap or pixmap is a type of memory organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits. Now, along with pixmap, it commonly refers to...
. 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
Page description language
A page description language is a language that describes the appearance of a printed page in a higher level than an actual output bitmap. An overlapping term is printer control language, but it should not be confused as referring solely to Hewlett-Packard's PCL...
such as PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
, Portable Document Format
Portable Document Format
Portable Document Format is an open standard for document exchange. This file format, created by Adobe Systems in 1993, is used for representing documents in a manner independent of application software, hardware, and operating systems....
, XPS
XML Paper Specification
Open XML Paper Specification , is an open specification for a page description language and a fixed-document format originally developed by Microsoft as XML Paper Specification that was later standardized by Ecma International as international standard ECMA-388...
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.
Raster image processing is the process and the means of turning vector digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
information such as a PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
file into a high-resolution raster image.
Originally RIPs were a rack of electronic hardware which received the page description via some interface (e.g. RS232) and generated a "hardware bitmap output" which was used to enable or disable each pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
on a real-time output device such as an optical film scanner.
A RIP can be implemented either as a software component of an operating system or as a firmware program executed on a microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
inside a printer, though for high-end typesetting, standalone hardware RIPs are sometimes used. Ghostscript
Ghostscript
Ghostscript is a suite of software based on an interpreter for Adobe Systems' PostScript and Portable Document Format page description languages.- Features :...
and GhostPCL are examples of software RIPs. Every PostScript printer contains a RIP in its firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
.
Earlier RIPs retained backward compatibility with photosetters so they supported the older languages. So, for example Linotype RIPs supported CORA (RIP30).
Stages of RIP
- Interpretation: This is the stage where the supported PDLs (Page description languages) are translated into a private internal representation of each page. Most RIPs process pages serially so the current machine state is only for the current page; i.e. one page at once. Once a page has been output the page state is discarded to ready it for the next page.
- Rendering: A process through which the private internal representation is turned into a continuous tone bitmap. Note that in practical RIPs, interpretation and rendering are frequently done together. Simple languages were designed to work on minimal hardware so tend to "directly drive" the renderer.
- Screening: In order to print, a continuous-tone bitmap is converted into a halftoneHalftoneHalftone is the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size, in shape or in spacing...
(pattern of dots). Two screening methods or types are Amplitude Modulation (AM) screening and stochastic or Frequency Modulation (FM) screening. In AM screening, dot size varies depending on object density—tonal values; dots are placed in a fixed grid. In FM screening, dot size remains constant and dots are placed in random order to create darker or lighter areas of the image; dot placement is precisely controlled by sophisticated mathematical algorithms.
A RIP chip
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
is used in laser printers to communicate raster images to a laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
.
RIP Providers
- EG-DocRIP(printer drivers not available) can interpret several printer languages or document formats - HP PCL5, XL, Adobe PostScript Level3, Microsoft XPSXML Paper SpecificationOpen XML Paper Specification , is an open specification for a page description language and a fixed-document format originally developed by Microsoft as XML Paper Specification that was later standardized by Ecma International as international standard ECMA-388...
, W3C XHTML-MP, and render to raster image. - ImageNest RIP (Non windows OS)can layout multiple raster and PostScript files onto a single page. File support includes EPS, PDF, PS (Postscript) Camera RAW, DNG, TIF, JPG, GIF, PNG, HDR (High Dynamic Range), and other formats
- Harlequin RIPHarlequin RIPThe Harlequin RIP was first released in 1990 under the name “ScriptWorks” running as a command-line application to render PostScript language files under Unix...
renders from PostScriptPostScriptPostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
, PDF, XPSXPSXPS may refer to:* X-ray photoelectron spectroscopy XPS, also known as ESCA* Exopolysaccharide, or extracellular polymeric substance, a sliming substance secreted by bacteria and responsible for cells adhesion onto surfaces and in biofilms...
, PCLPrinter Command LanguagePrinter Command Language, more commonly referred to as PCL, is a page description language developed by Hewlett-Packard as a printer protocol and has become a de facto industry standard. Originally developed for early inkjet printers in 1984, PCL has been released in varying levels for thermal,...
etc. for use in desktop printers, digital production presses and prepressPrepressPrepress is the term used in the printing and publishing industries for the processes and procedures that occur between the creation of a print layout and the final printing...
. - RipExpress and PrintExpress Adobe CPSI based RIPs from IPA Systems Ltd.