Page 148 - Graphic Design and Print Production Fundamentals

5.3 Colour

Wayne Collins

The second challenge with implementing WYSIWYG for electronic documents that are imaged on
substrates is managing colour expectations. Chapter 4 discussed the challenges of colour management
from the perspective of how we see colour, measure it, and manage output devices with ICC profiles. In
this chapter, we will explore colour management from the perspective of how we recognize and manage
the ICC profiles that are embedded in client documents. We will also explore the preflight issues in
managing spot colours in documents. This will also lead us to a discussion of trapping for lithography
and flexography.

To design with colour in computer graphics software, we must understand how the software generates
the colour values. Page layout and illustration software usually have several systems for creating colour
on a page. The colour settings or colour preferences attached to a file can change from one document
to another or in the same document restored from one computer to another. If a designer uses the RGB
colour model to specify the colours in a document, the colours on the monitor can change depending
on the translations done to the colour settings. This is a major turning point for designers creating
documents intended to stay in the electronic media. No one pays much attention to how a particular
colour of red is rendered from one web browser to another. Designers pay more attention to how the
colours interact relative to one another in web-page documents. It is only when we image a computer
graphic on a substrate that we must pay attention to rendering the exact hue of red from one device to
another. Coca-Cola has very exact specifications for the red used in its documents that tie into its brand
recognition. So designers for documents intended for imaging on substrates must use colour models that
are proven to render exactly the same results from one output device to another.

Pantone Colours

This is a lofty ideal that the graphic communications industry aspires to. There are systems in place that
are proven to render very accurate results. There are challenges in understanding the systems, and one
wrong step in the process and accuracy is destroyed. The process starts with how a designer chooses
colours in a document. The most-used system for choosing accurate colours was created by the Pantone
company. Pantone has developed a library of ink recipes that are published as swatch books. A designer
can buy a printed book of a library of colours that matches an electronic library that can be imported
into computer software programs. Designers compare their on-screen rendering of a colour to the printed
sample swatch. If a designer is developing a corporate identification package with logos that use Pantone
123 and Pantone 456, the designer can be assured that the documents he or she creates will be imaged
with inks that have similar spectral values to the swatch books used to choose the colour. I say similar,
because the swatch books fade over time, and the substrates the books are printed on don’t usually match
all the substrates a corporate logo is imaged on.

It is also important to realize that the Pantone library was created to mix pigments for spot colour
inks rather than process colour inks. Spot colours are mixed independently and must each be applied

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