Computers: Jargon buster

Greyscales: A progressive series of shadings ranging from black through white, which are used in graphics programs to give detail to images in black and white. Not all monochrome monitors are capable of displaying greyscales.

Pen: Light pen or stylus, an electronic peripheral device that contains light sensors and can input information based on patterns of light and shade to the computer.

Scanner: A device similar to a photocopier or fax that uses light sensors to scan images on paper or other media and 'digitise' them - convert them into computer readable data. Drawings, graphics, photographs and other images can be input in this way and edited on the computer with image-processing software.

Tablet: A flat plastic rectangle imbedded with electronics that is used with a pointing device such as a light pen. It operates like a mouse, with movement on the tablet translated into various kinds of movement and marks on the computer screen.

Undo: A standard computer instruction that reverses an instruction, restoring an earlier version of a document or image.