Surface relief hologram

The most ubiquitous and popular type of hologram, mainly exhibiting a characteristic rainbow-coloured pattern. Surface relief holograms are mass-produced mechanically by embossing or casting a relief pattern or image into a thermoplastic film or a viscous coating on a...


A protocol for arranging the bars and spaces of barcodes for the encoding of numbers, letters and binary numbers.

Split duct process

Also known as rainbow printing. This is employed in offset printing where colours are intentionally allowed to overlap on the transfer cylinder producing a gradated effect.

Spot colour

Also known as a solid colour, this is any colour printed with its own ink, in contrast to process colour printing which uses four inks (cyan, magenta, yellow and black – or CMYK) to produce all other colours.

Structured Query Language (SQL)

The standard language used to communicate with relational database management systems (ie. systems which store and provide access to data points that relate to one another). SQL statements are used to perform tasks such as updating and retrieving data.