Oki 8c Plus User Manual

Colour Guide

Brilliant Colour from Oki

Thank you for choosing the OKIPAGE 8c Plus Colour Page
Printer.

The OKIPAGE 8c Plus offers brilliant colour printing at a fast 8
pages per minute on plain paper and 5 pages per minute on
transparencies - the OKIPAGE 8c Plus is the perfect workgroup
printer for a wide range of business applications.

The following pages have been conceived to provide the
reader with a broad overview of the issues related to colour
printing, in order that the best use of colour be made in the
applications chosen. The text is designed to describe the
technical issues in a manner that can be understood by anyone
involved in the preparation of colour documents.

Please also familiarize yourself with the Operator
documentation provided – this describes specific operational
details of the OKIPAGE 8c Plus set-up and configuration for
specific options.

We are sure that you will find the OKIPAGE 8c Plus an excellent
part of your departmental printing soloution. If you have any
comments with regard to the content of this document, then
please let us know through your local Oki representative.

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Contents

Brilliant Colour from Oki .............................................. 2

The use of colour ........................................................... 4

Colour perception ......................................................... 5

The electromagnetic spectrum ...................................... 6

Primary and secondary colours ..................................... 7

Additive and subtractive primaries .......................... 7

Additive primaries ............................................... 8

Subtractive primaries ........................................... 8

Neutral Colours ........................................................ 9

Colour Complements ............................................... 9

Colour wheel ............................................................... 10

The problems with using colour ................................. 11

Colour management systems .................................. 11

Specifying colour ........................................................ 12

Printing colour ........................................................ 14

Colour registration ................................................. 14

Colour adjustments ................................................ 15

The OKIPAGE 8c Plus printer driver ...................... 16

Print Modes ........................................................ 16

Halftone Settings ............................................... 17

Image Colour Matching .................................... 17

Manual Colour Ajustment ................................. 18

Glossary ....................................................................... 19

English

Colour Guide 3

The use of colour

Recent advances have brought colour to the desktop in a way
that could not have been imagined a decade ago. It has been
shown that using colour in print can increase memory
retention by up to 65% and readership by as much as 40%,
not to mention the added impact that it provides. As colour
becomes more and more accessible it is essential to
understand the importance of colour and how best to use it.

People use colour for different reasons; it has become a very
important tool and is used widely in marketing to grab
attention and communicate ideas, and when used effectively
can alter the viewer’s perception.

Colour can be used in text documents as well as for graphics.
It can be used to emphasise headings or particular words
which would otherwise be lost in the vast array of black and
white. Colour adds impetus to a company logo and can be as
important as the design itself. The use of colour also makes a
document easier to comprehend and can convey information
at a glance. For example, using red to highlight negative
figures in a spreadsheet.

The use of colour should be considered an integral part of
any presentation or document and not added at the end as an
afterthought.

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Colour perception

The following examples list some widely used colours and
their significance:

This is a very powerful and passionate colour. The power and passion

that it portrays has made it a favourite for many exotic sports cars.

Unlike red, green is a very calming and ‘natural’ colour. It signifies

trees, grass and plant life in general. It is soothing and perhaps associated

with a stroll in a field. As well as the calming side of green, it is also the

colour of envy.

A cool and refreshing colour. It is the colour of summer skies and a

clear blue sea which produces a calming effect. Dark blues are associated

with wealth and dignity and also have names that suggest these virtues

– Royal blue, Navy blue, etc.

This is really an absence of colour and the contrast that it provides with

other colours has made it one of the most widely used. Black is usually

associated with night and darkness

The colour of pure snow and in itself suggests purity. It is used in

hospitals to portray an air of cleanliness and sterility. Like black, white

can be paired with most colours and is therefore very popular.

In short, colours can be used effectively to send their own
message, regardless of the message that they are supporting.
The colours used within a message are seen and automatically
decoded before the message itself has been read. This
underlines the importance and effectiveness of using colour.

Colour does not exist by itself but is dependent on the
presence of:

• a light source

• an object

• an observer

Our perception of colour involves light from a source being
reflected off, or transmitted through, an object and entering
the eye.

English

Colour Guide 5

The electromagnetic spectrum

Light interacts with an object and what we see is the final
result of that interaction. An object can reflect, transmit or
emit light. A reflective object absorbs some sections of the
visible spectrum and reflects the rest. What we see is the
reflected portion. An object removing wavelengths at the ultra
violet end for example, will appear red in hue. A transmissive
object allows light to pass through it and may absorb a section.
The colour of the object in this case, will depend upon the
wavelengths of light that are allowed to pass through. An
emissive object emits light and the appearance of the light
will depend on the wavelengths emitted. In short, the
composition of the light and its interaction with the object
will define the colour we see.

1 micrometre = 1×10-6metre (0·001mm)

1 nanometre = 1×10-9metre (0·000001mm)

1 picometre = 1×10

1 fentometre = 1×10

-12

metre (0·000000001mm)

-15

metre (0·000000000001mm)

All colours we can see fall into what is the visible part of the
electromagnetic (EM) spectrum. The visible portion of the
EM spectrum is minute and although we are ‘blind’ to the
rest, the part we can see has a significant effect on our
perception of everything around us.

If light containing all visible wavelengths in balanced
quantities is detected, then white light is seen. If there is an
absence of all wavelengths then black is perceived. The
infinite combination of different wavelengths give rise to what
we perceive as colour. So colour is light.

When our eyes receive information containing a strong
content of a particular wavelength then we interpret that as a
colour. A strong content around 700nm (0.0007mm
wavelength) is interpreted as red and at the other end of the
scale, 400nm is interpreted as violet.

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Primary and secondary colours

Additive and subtractive primaries

In theory, all colours can be made up from a very small group of ‘colour elements’. There are three primary colours, and all other colours can, in theory, be obtained by mixing the primary colours in varying proportions. Mixing two primary colours in equal proportions produces what is known as a secondary colour.

Primary colours can be split into two categories which are
termed additive and subtractive. It is important to note the
difference between mixing additive primaries and subtractive
primaries. For example mixing red and green inks will
produce a ‘muddy’ brown, whilst red and green light mixes
to give yellow. So in which way do the two models differ ?

GREEN

CYAN

BLUE MAGENTA

YELLOW

RED

English

Colour Guide 7

Additive primaries

Subtractive primaries

Video technology such as computer monitors and television
screens use the additive model. The additive primaries are
Red, Green and Blue (RGB). Starting from black (lack of
colour) and adding red, green and blue in equal quantities
will generate shades of grey with white being generated with
full, balanced intensities of all three. Mixing the three colours
in different quantities will generate intermediate colours.

Cyan, Magenta and Yellow (CMY) are known as the
subtractive primaries and are commonly used in printing
processes. In this case we start with a white background
(usually paper) and add translucent inks of cyan, magenta
and yellow to subtract certain wavelengths of light. For
example, cyan ink on a page appears to be this colour because
the ink removes components of red light and reflects green
and blue, which we perceive as cyan.

Traditional CMYK print

standard dot display Trinitron™ display

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