About colour

Printing in colour

There are two different ways colour can be applied to paper in colour printing.

Spot (solid-colour) printing
This method applies a premixed colour of ink to the page. Spot colour is useful for documents that require only a few colours, such as newsletters, brochures and stationery. Spot colour is also used to match specific colours very closely. This colour is usually identified by a colour system such as the Pantone Matching System.

Process (four-colour) printing
This applies four or more standard ink colours (the basic four are cyan, magenta, yellow and black) in very fine screens so that many thousands of colours are created. Process colour is more useful for printing photographs, paintings and very complex coloured images.

In some cases, both spot colour and process colour can be used on the same document. For example, a company brochure may include colour photos (process colour) and a corporate logo (spot colour).

Design choices will affect cost!
The cost of printing colour documents is usually related to the number of ink colours used. As process colour requires four or more inks, spot colour can be cheaper if you use fewer than four colours.

Spot colour also has the advantage of printing a wider range of clean, bright colours. If a colour seems smooth and even no matter how closely you look, it's probably printed with spot colour.

About Pantone colour

Your printer or designer will often refer to a specific colour using a 'Pantone number'. If you are going to talk about colours in this context, you need to know a few basics. The Pantone Matching System ® is the definitive international reference for selecting, specifying, matching and controlling ink colours

It is used by artists and commercial printers to select, specify and match colours very precisely. Many logos are created with specific Pantone colours that can be very closely reproduced. By using Pantone colours designers can be confident that their output will match their expectations.

Each Pantone number relates to a unique colour in a colour palette.

• The Pantone solid colour palette This has 1,012 colours in pre-mixed Pantone printing inks. The colour reference will contain a 3 or 4 digit number followed by the letter C, U or M. C = Coated, U = Uncoated, M = Matte Coated. This refers to the appearance of the colour when printed on coated, uncoated or matte-coated paper. The appearance of each colour will be slightly different depending on the paper used and Pantone, therefore, supply accurate reference samples for each colour, printed on each of these three types of paper.

• The Pantone process colour palette For four-colour (CMYK) printing, the Pantone Process Colour System ® specifies more than 3,000 colours made up of varying percentages of cyan, magenta, yellow and black. If the item to be printed includes colour photographs, or is made up of many different colours, the printer will normally use the 'four-colour' (process) system.

It is not always possible to accurately match a 'solid' colour by mixing cyan, magenta, yellow and black so a compromise is therefore necessary. Pantone produce colour guides to deal with this issue. The Solid to Process Guide shows each Pantone 'Solid' colour and its nearest 'Process' colour equivalent.