Indexed Colour

A colour system that defines a palate of colours to be used in a specific image. This makes the file size small and manageable.

JPG or JPEG

Joint Photographic Experts Group. Standardised image compression format developed by the Joint Photographic Experts Group. Used for compressing full colour and greyscale images. The standard format for digital camera files.

Kelvin

A unit of measure on the absolute temperature scale. Defines the quality of a light source by measuring the absolute temperature of a black body that would radiate equivalent energy. Colour calibration software can help determine the Kelvin value of your monitor and adjust the display settings to suit the Kelvin rating of the light bulbs used in your office environment.

Kerning

Adjusting inter-character spacing of letters. Typically for pairs of letters that need special spacing to make them more easily recognisable and readable.

Landscape

The orientation of a page so that the longest edge is horizontal.

Leading

All the characters in a page of type rest on an imaginary line called a baseline. Leading is the space between one baseline and the next. The origin of the term is found in the history of printing where pages were set using metal type. Long strips of lead of equal thickness were used to sit the lines of metal type on, hence "Leading". Software programs often refer to leading as "line spacing".

Letterpress

A method of printing that was used exclusively up until the 1980s and the invention of offset printing. The printing "plate" has a raised surface composed of raised metal letters and other elements which is then inked and pressed mechanically onto the printed sheet.

Line Art

Single colour logos, drawings or diagrams that consist of only black and white without intermediate greyscale information. See also 1-bit Black & White Bitmap.

Lithography

A method of printing from a plane surface. The printing image is ink-receptive, the non-printing areas are ink repellant.

Lossless/Lossy Compression

Lossless compression will retain all of the file's original image data. The TIF format using LZW compression is considered and example. Lossy compression will sacrifice user-definable amounts of image quality and detail to reduce file size. An example is JPEG compression.