ABSTRACT
The ideal printing technology would be one able to emulate the traditional mixing of liquid paints in the proportions necessary to produce the desired colour at every point on the paper. Most available technologies are unable to do this. Certainly not the colour dot matrix printer, as the 'ink' is not in a liquid form and is deposited on the paper by firing pins to impress coloured ribbons against the paper. Similarly, colour laser printers, which use dry coloured toners, have no means of mixing the toners. Even inkjet printers, which use real liquid inks, can either expel a minute droplet of ink at each
Printer driver software Printer driver software .is becoming increasingly 'intel-
ligent', as vendors strive to make it easier for users to optimise colour output. Intelligent driver technology is marketed under a variety of names-Xerox' s Intelligent Color, Hewlett Packard's ColorSmart, Tektronix's TekColorand QMS's QColor, for example. The basic principle behind these technologies is that the contents of a page are analysed by the driver as it is
Colour output
Digital Colour in Graphic Design
those dots can be configured in different ways within the computer/printer subsystem. This is where page description languages (PDLs) play an important role. The minimal type of printer architecture is a nonintelligent device which simply outputs a bitmap that has been created by the host computer. Such are the so-called GDI (Graphics Device Interface) printers which are designed to work with Windows; the GDI
commands used to display the screen image are directly converted to bitmap form by the host PC, stored in the PC' s memory and then sent to the printer for output. GDI printers are relatively cheap, since they do not require processing power or large amounts of internal memory, instead relying on the power and memory of the host PC.
