CREATING A DIGITAL FILE: Details

DEFINING COLOURS

When defining colours, you must refer to a printed tint guide before entering values in the colour palette. That’s because RGB colour monitors do not accurately represent ink on paper - whether CMYK process tints or PANTONE® spot colours. Many desktop programs allow you to specify colours in two ways:

• as spot colours by product name (such as PANTONE)
• as process colour by setting CMYK percentages

Process Colours
If elements of your book are going to be printed as four-colour process, "process separation" must be selected when you create a new colour. If you don’t select this option, the colour will be created as a fifth "spot" colour in the job.

Spot Colours
When specifying spot colours, set the process separation colour to "Off" to ensure that the colours are not generated as a CMYK match. This is the most common error encountered when defining spot colours.

Changing Spot Colours to Process Equivalents
When specifying process tint matches, be aware that different programs can generate different CMYK percentages for the same PANTONE colour. Some software developers have ignored the recommended PANTONE CMYK process tint percentages and have substituted their own. We recommend using a PANTONE swatch book for selecting and matching colours. The PANTONE Matching System (PMS®) is the North American standard for colour specification.

Naming Conventions
The naming of colours is important because a printing plate is output for each colour listed in a palette (CMYK and any spot colours) used in a document. For instance, using the colour "spot Black" instead of Process "Black" will result in two separate plates. Colour names must also be consistent among applications. If one of your applications uses a slightly different naming convention for its colours (i.e. PMS 335 CVC vs. PMS 335 CV), two different plates will be imaged when the files are processed, even though the colours themselves match.

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