Systems that circulate ink continuously though either their storage cartridges or bottles, or through and past the printhead. This is usually to prevent heavy particles from settling under gravity.

In any printing process it’s important to make sure that the printed image goes where you want it on the substrate, and can be repeated in the same position every time. In multi-colour printing this is particularly vital because the colours have to align on top of each other in the correct position, otherwise unwanted light and dark edges will show, and halftones will appear blurred.

In print terms, it’s a measure of the number of individual dots a printer or exposure system can produce within a unit of distance, typically given as dots per inch. In optics (where the term originally comes from), resolution describes the amount of detail a focused lens can project onto a surface and is usually described as line pairs per millimetre (or inch).

Red, Green, Blue, the main colours that the human colour vision system , perceives. Three types of cone cells in the human retina respond to different spreads of wavelengths in the visible spectrum. The brain perceives these responses as colour, with different proportions of red, green and blue giving all the colours that the human visual system can perceive.

Stands for Raster Image Processor, also called a Renderer.