CIE LAB |
The 1976 CIE colour space transformation with the dimensions L*, A* and B*, in which equal distances in the space represent approximately equal colour differences. |
| CMYK |
Short for the subtractive primary colours of commercial printing: cyan, magenta, yellow and black. |
| Colour management |
The process of matching colours and keeping them visually consistent between devices which have different colour capabilities. |
| Densitometer |
An instrument used to measure and monitor the density of ink and colour when printing. |
| Dpi |
Dots per inch, a common unit of measurement to indicate the dot resolution of printers, scanners and computer displays. |
| EPS |
Encapsulated PostScript, a Post-Script-based file format for pictures which can then be conveniently imported into a page layout. EPS is most commonly used for vector graphics but has partly been superseded by PDF. |
| FPO |
For position only, referring to a low resolution version of a digital image which can be conveniently used in page make up and only replaced with the original high resolution version at the output stage. |
| GCR |
Grey Component Replacement, the act of replacing neutral greys in an image that have been produced using a mix of process colours (cyan, magenta, yellow) with a black tint only. This reduces the amount of ink being applied to the paper in these areas when printing. Sometimes referred to as, UCR under colour removal. |
| GIF |
Graphic Interchange Format, an image file format with built in compression, commonly used in web pages. Because of it’s 256-colour limitation and having been designed for on-screen use only, GIF is not suitable for photographic or press output. |
| Greyscale |
An image composed of greys as opposed to colour or purely black and white. |
| Gsm |
Grams per square meter, used to describe the weight of a sheet of paper. Typically when the weight of a sheet is 200gsm or more, it is described as a board. Typically when the weight is approximately 350gsm or more it gets measured in microns (thickness) instead. |
| Halftone |
Printed colour is an illusion produced by a fine mesh of overlapping dots made up of ink primaries, typically cyan, magenta, yellow and black. This mesh is known as a halftone screen. Photo images reproduced in print are commonly referred to as halftones. |
| ICC profile |
Created by the International Colour Consortium, a body established in 1993 to standardise colour management on digital systems. The ICC profile is the characterisation information of a device’s colour rendering and reproduction capabilities, saved as a file. |
| Imposition |
The process of placing the pages of a document into their relative positions on the printing plate, according to the size of the plate and the number of pages. The printed sheet can then be folded and trimmed and is ready for binding. |
| Line screen |
Halftones were originally produced photographically by overlaying a photo print with a transparent screening sheet bearing a close mesh of ultra-thin lines. The resolution of this mesh – even when created digitally – is referred to as a line screen or halftone screen. |
| Lpi |
Lines per inch, being the resolution of a halftone screen. |
| PDF |
Portable Document Format, a cross-platform, graphically rich and self-contained document file format based on PostScript technology. |
| Pixel |
A contraction of the term picture element, a single coloured dot in a computer-based image. |
| PMS |
Pantone matching system, recognised as being the most common colour control system used in the manufacture of printing inks. Pantone create colour specifications to be used in the manufacture of inks. Pantone also supply colour reference charts for the purpose of selecting and matching colours. |
| PostScript |
The PostScript language was developed by Adobe, to provide a means of describing integrated text and graphic data as a single data stream. Together with Apple’s Macintosh computer, the LaserWriter print engine and Aldus’ Pagemaker. PostScript was one of the foundation technologies of the desktop publishing revolution. |
| Process colours |
The subtractive primary ink colours of printing: cyan, magenta, yellow and black. |
| Resolution |
A generalised term to express the density of pixels addressable by a computer imaging device (printer, scanner, camera or display), usually expressed as dots per inch (Dpi). |
| RGB |
short for the additive primary colours: red, green and blue. |
| RIP |
Raster image processor (rip), the software engine which converts PostScript page data to a high resolution bitmap sent to an output device. |
| Spectro-photometer |
An instrument which measures the characteristics of light reflected from or transmitted through an object, interpreted as spectral data. |
| Trap |
The area where adjacent coloured areas on printed matter are made to overlap slightly. |
| UCR |
Under colour removal, where the three colours, cyan, magenta and yellow are reduced in favour of black. |
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