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.
2 OKIPAGE 8c Plus
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.
4 OKIPAGE 8c Plus
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.
6 OKIPAGE 8c Plus
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
8 OKIPAGE 8c Plus
Neutral Colours
In theory, a combination of the three subtractive primaries
will produce black. In practice however, pigments used in
inks are not perfect and usually give rise to a dark green/
brown. For this reason, in many colour output devices, a
separate black ink is used to produce greys and black (in
shadows and black text for example). This is the CMYK
model and is the method most widely used in the colour
printing and printer industry. The OKIPAGE 8c Plus uses separate
cartridges of cyan, magenta, yellow and black toner to
generate high definition colour images for the workgroup or
networked environment.
Although the term ‘colour’ is applied, neutral colours do not
have properties of hue or saturation. They are described in
terms of lightness only. The neutral colours are black and
white and all shades of grey in between. A balanced mix of
cyan, magenta and yellow yields a neutral colour or black
(in theory). The same effect can be achieved with the additive
primaries by having an equal mix of red, green and blue light.
Colour Complements
Complements are pairs of colours that combine to produce a
neutral colour. It can be seen from the above that balanced
quantities of all three primaries produce a neutral. Mixing
two primaries produces a secondary colour. Mixing this
secondary colour with the remaining primary colour produces
a neutral colour. For example:
CYAN + MAGENTA + YELLOW = NEUTRAL
— red (magenta + yellow) + cyan = NEUTRAL
— green (yellow + cyan) + magenta = NEUTRAL
— blue (cyan + magenta) + yellow = NEUTRAL
This relationship can be applied to all colours and is shown
in more detail in the following section.
English
Colour Guide 9
Colour wheel
The relationship between colours can be best shown on what is
known as a colour wheel. The hue value of a particular colour is
expressed in degrees. Red for example is at 0° and green and
blue are located at 120° and 240° respectively. The subtractive
primaries, yellow, cyan and magenta are located at mid points
between these.
The colour wheel shows the following relationships:
• the additive primaries are displaced by 120° from each other.
• the subtractive primaries are displaced by 120° from each other.
• each colour is a secondary colour of the two colours either side of
it. For example, mixing equal quantities of yellow and magenta
will produce red.
• a colour is directly opposite its complement.
We can continue to mix neighbouring colours on the colour
wheel to produce further, intermediate colours. The number
of colours on the colour wheel now doubles to twelve (as shown
below). Repeating the procedure a number of times produces a
colour wheel with subtle changes of hue from neighbour to
neighbour.
Colour Wheel
showing RGB (circles), CMY (squares)
and their first set of intermediate colours.
10 OKIPAGE 8c Plus
The problems with using colour
Colour management systems
As already explained, a computer monitor, where an image is first
viewed, and a printer which produces the final document use
different methods to generate colours. Indeed they are based
around a different set of primaries (RGB for monitors, CMYK
for printers). Monitors do not generate a full range of perfect
colours and neither do printers. There is a limit on how many
colours a monitor or printer can generate. This is known as a
device’s colour gamut. Some colours can be reproduced by
both devices, while others can be displayed on a monitor but
cannot be printed or vice versa. This in practice may lead to a
colour print not resembling the original on-screen image. So
what has happened?
Images (graphics and text) can be captured through scans or
digital photography, or input directly into the PC via
applications programs. However the original image is
obtained, it will be displayed and manipulated in RGB colour
space (on-screen) and finally converted to CMYK for print.
Each of these processes requires data conversion/
manipulation. An image seen on a computer monitor relies on
the monitor’s ability to reproduce the image and represent
colours within it. Adjustments such as brightness, colour and
contrast also tailor the image to the preference of the viewer
rather than a display of true colour. The data sent to the printer
may not be adjusted to allow for imperfections in the inks used.
Colour Management Systems (CMS) such as those found in the
OKIPAGE 8c Plus printer driver, allow for any mismatches that
may occur between the RGB and CMYK conversion process.
Colour matching systems go a long way to ensuring a better match
between the input data and printed result but cannot always allow
for monitor adjustment or a variation in paper stock. Paper can
sometimes appear blue or cream in hue which will have an effect
on the light reflected from the page and therefore change the
appearance of some colours. The texture of the paper used will
affect the way that light is scattered and may also result in patches
of light or dense colour. It is therefore best to find and adopt a
paper that provides you with the best results. This of course may
be a process of trial and error, but some recommendations are
given in the User’s Guide.
English
Colour Guide 11
Specifying colour
Although colour has its obvious benefits, it has also created a
whole new set of problems that need to be dealt with:
• It is important not to go overboard and add dashes of
colour without thought as this will undoubtedly have a
negative effect on the whole purpose of using colour.
• Using colours which are considered garish will also affect
the way in which your document or presentation is
perceived.
• The proximity of colours is also an important factor and it
is best to consider the result when certain colours are
paired.
To minimize any problems it is important to use colour with preplanning and a great deal of care. If specific colours are of
paramount importance (such as those in a company logo) then it
is best to print these colours beforehand and note the composition
that gives the closest match to the required colour. Then use the
component amounts regardless of what is displayed on the
monitor.
There are many different ways to specify colour and there are
many different models to cater for this. The colour wheel as
already shown, is a two-dimensional view of the HSL model
which is based on Hue, Saturation and Lightness as components
for specifying colour. The third dimension in this case is lightness
and describes the tendency towards black or white.
HUE
SATURATION
LIGHTNESS
Commonly used models are:
• HSL • HSB
• CMY(K) • RGB
• CIE, CIELab, CIELuv • YCC
12 OKIPAGE 8c Plus
Each of the models have their benefits and disadvantages and
are useful in particular situations. Most applications will have
support for the RGB model which (along with CMYK) is perhaps
the simplest to use. This model is used to specify colours by
varying the proportions and levels of the red, green and blue
components.
The amount of red, green and blue present in a colour is usually
expressed as a number from 0 to 255. Less commonly it may
also be expressed as number between 0 and 65535 or as a
percentage. Converting between the systems is straight
forward and a few examples are given below:
Example: To achieve a colour that is described as 100% red,
50% Green and 40% blue…
255 Colour scale: 100/100 × 255 = 255 red
50/100 × 255 = 128 green
40/100 × 255 = 102 blue
65535 Colour scale: 100/100 × 65535 = 65535 red
50/100 × 65535 = 32768 green
40/100 × 65535 = 26214 blue
The printout from this set of numbers should produce a colour
close to the original. Due to the variation in printer inks however,
it may be necessary to make minor adjustments until the right
combination is found. Once a colour match is obtained, the
RGB components should be entered regardless of the colours
displayed on-screen. To maintain colour consistency it is
recommended that OKI original consumables are used as they
are specifically manufactured for the OKIPAGE 8c Plus.
English
Colour Guide 13
Printing colour
Colour registration
No matter how colours are specified, the printer is only able to
use a combination of three colours plus black to generate an
image on paper. To achieve this the printer uses processes known
as halftoning and dithering. Each addressable picture element
(pixel) on a monitor screen or printed output contributes to what
we see in the final image. The pixels are placed in close proximity
so the eye is unable to resolve individual dots. Colours of
adjacent pixels appear to merge and produce a new colour. Using
dot patterns of a given set of colours to generate new colours is
known as dithering. Shades of grey can be generated by using a
similar technique of black dot placement. This technique is
known as halftoning and gives rise to what we perceive as a
continuous tone image. Examples of dither and halftone are
shown below:
dither pattern halftone pattern
The entire printing area is split into sections known as cells
(much like a grid). The patterns within the cell are then altered
to obtain the required amount of greyscale. An area of an
image containing 50% grey will contain cells that have half
of the dots within the cell printed with black and the other
half left empty.
The CMYK printing process, as already stated, uses overlapping
inks of cyan, magenta and yellow. To produce the best possible
output, the colours must print in specific positions so that
overlaps and dithering are accurate. If the colours are not aligned,
the resulting print will have colour shifts (colours produced
where incorrect colours overlap to produce an undesired colour)
or appear blurred. Using black to print grey and also black in
text eliminates the problem in these instances but not when
colour is constructed from two or more of the process primaries.
The print below shows how registration problems can cause
undesired effects:
If your OKIPAGE 8c Plus shows problems as described above
then refer to your User’s Guide in the section entitled “Adjusting
Colour Registration”.
14 OKIPAGE 8c Plus
Colour adjustments
Certain images such as bitmaps, sometimes print with a strong
hint of a particular colour. Images that appear fine when viewed
on a monitor may not necessarily print that way due to the reasons
described previously. The colour that appears to dominate the
picture will vary depending on factors such as the scanner (or
other input device) having a bias towards a particular colour, or
the monitor’s ability to represent certain colours on-screen. To
compensate for this, the OKIPAGE 8c Plus has a colour adjustment
system that can reduce the amount of any of the process colours
put on the page in relation to the others. If you run Windows on
your computer, the printer drivers supplied with your printer
provide these adjustments. These are outlined in this manual
and explained in more detail in the driver’s on-line help. (Click
the Help button in any driver dialogue box.). For other
operating systems or drivers, the printer’s Operator Panel
menus provide similar adjustments, detailed in the
OKIPAGE 8c Plus User’s Guide.
This is useful if, for example, you find that all of your graphics
have a tendency to contain too much blue. To compensate for
this, you could reduce the amount of cyan or magenta as it is
these two colours that combine to produce blue. Bear in mind
that other colours containing cyan or magenta will also be
affected. An alternative would be to increase the amount of
yellow. This has the advantage of increasing colour saturation
while balancing the image.
Another method of decreasing strong colours is to increase the
lightness setting in the printer driver. To compensate for this,
the saturation setting must be stepped down accordingly. As a
rule, the saturation should be set down an equal number of steps
to the level that the lightness has been stepped up.
English
Colour Guide 15
The OKIPAGE 8c Plus printer driver
There are various features designed to allow you to achieve the
best results with your OKIPAGE 8c Plus. The Colour Options
tab within the printer driver provides a list of colour matching
techniques and adjustments which can be applied to your
graphics and text to provide the optimum balance of colour
on your document. The options and adjustments that can be
made are described below. Clicking on the properties button
after a print request has been made and then selecting the
colour options tab will display the following:
The colour matching option is set by default, as is the ‘Auto’
halftone setting and ‘Printer Colour Matching’. These settings
will produce the best results from your OKIPAGE 8c Plus in
most situations. It is sometimes necessary to use other settings
to allow a certain effect to be achieved. The selectable items are:
Print Modes
Colour Matching
This option, when selected, allows the printer driver to adjust
output data to specify how colours in the document will
match those printed.
Greyscale Printing
All print data is sent as monochrome (black and white) with
colours being output as greyscale. Only the black toner
cartridge is used in this instance.
Manual Colour Adjustment
This leaves details such as settings for halftone, colour,
lightness and saturation to the user. This allows maximum
flexibility but requires thought and pre-planning before use.
16 OKIPAGE 8c Plus
Print Colour Swatch
This button prints a sample of each colour together with its red
green blue component values. A choice of 4 pages or 12 pages is
available, depending on the colour range you want to see. If you
have problems matching particular screen colours to the printer,
simply print a colour swatch, find the colour you want to print,
and note its RGB component values. Then input these into your
application program to achieve an exact match on the printer.
Image Colour Matching
Printer Colour Matching
This colour matching technique uses OKI colour matching
technology to match colours in the document to those
printed. This matching technique is optimized for the
OKIPAGE 8c Plus and replaces the one normally performed
by Windows.
English
Halftone Settings
Auto
This selects optimum dithering for most print jobs.
Photo
This is only found under the bitmap tab and prints pixels as
close as possible to the specified density. Any variation
from the data specified is taken in to account when printing
neighbouring pixels. Neighbouring pixels will be printed
lighter or darker to compensate for the variation of the
original pixel. This method produces smooth transitions of
colour within an image.
Graphics/Text
The driver selects fixed size halftone cells which are useful
when printing charts, graphs or other business graphics.
Colour Guide 17
Matching Off
No colour matching is performed. This means that printed
colours will not necessarily match those specified within
the document.
Manual Colour Ajustment
Vivid Screen Match
Colours are printed as closely as possible to the colours
seen on screen, emphasizing vividness.
Vivid Colour
Colours are printed as brightly and vividly as possible, i.e.
colours are more saturated and vibrant.
Screen Match
Colours are printed so that they resemble those on-screen.
This may not work in practice because brightness, chroma
and contrast settings on each individual monitor cannot be
allowed for.
Unadjusted Colour
No colour matching is performed and data is sent directly
to the printer. Printed colours may not match those specified
within the document.
Lightness
This allows the image brightness to be adjusted so that
colours within it tend to appear closer to black (negative
adjustment or darker) or white (positive adjustment or
lighter).
Saturation
This adjusts all colours within the image so that they appear
dull (negative adjustment) or vivid (positive adjustment).
18 OKIPAGE 8c Plus
Glossary
Brightness
Along with hue, and saturation, brightness is one of the three dimensions
of colour. It is the property that describes the intensity of light reflected
or transmitted by an object or source, independent of hue or saturation.
Cluster-dot screening
This is a halftoning method that uses multiple pixels that vary from small
to larger dots as the colour gets darker. It is characterized by a polka-dot
look.
Colour gamut
The range of colours that a device can produce is known as its colour
gamut. Devices are unable to produce all colours that occur in nature so
their colour gamut is a subset of this.
Colour Management System (CMS)
A system used to communicate colour fidelity across devices such as
input, display and output to ensure that the best colour rendition possible
is given at all times.
Colour mapping
This is the translation of colour representation from one device (or system)
to another.
Colour models
A colour model is a system that allows colours to be arranged or identified.
There are various models in existence, with some more suitable to specific
applications than others.
RGB
Computer monitors for example, use red, green and blue phosphors to
display images and colours are specified using the RGB model.
CMY(K)
Cyan, magenta, yellow and black are the inks used in the four colour
print process and there is a model used to describe this. Due to the
imperfections in printing inks, black is added rather than produced by
mixing the other three inks. Black is identified as ‘K’ to avoid confusion
with other colours such as blue.
HSL
Colours are defined by hue, saturation and lightness.
HSB
Colours are defined by hue, saturation and brightness. The dimensions
are similar to the HSL model but the HSB model is related to the RGB
system.
English
Colour Guide 19
YCC
This system was developed by Kodak for encoding colour images for
display on video monitors. RGB values are converted to a luminance
component (Y) and chromatic components (C1) and (C2).
CIE
In 1931 the Commission Internationale de l’Eclairage (CIE) devised a
colour system based on the human visual system and is an accepted
standard. This system is not linear and difficult to interpret. There have
been modifications to the system that have given rise to CIELab and
CIELuv.
Colour separations
Each of the process colours are printed separately and must therefore be
specified individually, as the colour is needed. Image data is therefore
split into the primary colours (plus spot colours) before printing.
Colour space
This is a method of describing colour. Some systems are device-dependent
such as RGB and CMYK. The CIE system is a device independent colour
space. Note that all colour models are not colour spaces in their own
right.
Colourants
These are the colours used by a device to reproduce colour. A printing
press uses the CMYK colourants.
Density
In this context, there is no relation to the mass and volume of the object,
but is the ability of the object to absorb light. The more light absorbed,
the higher the object density.
Dithering
A technique where pixels of different colours are placed in close proximity
to give the illusion of another colour as perceived by the human visual
system.
Dot gain
During the printing process, inks may spread causing dots on a page to
print larger than intended. This results in darker tones and colours. The
problem can be compensated for by careful adjustment.
Error diffusion
This is usually associated with halftoning but can also be used with dither.
The error between a pixel and its intended value is propagated to adjacent
pixels to produce a balanced overall effect. Results may sometimes appear
grainy.
20 OKIPAGE 8c Plus
Grayscale
Differing shades of grey ranging from black to white. Eight bits of data
will produce (28) 256 shades of grey.
Halftoning
A printed image is composed of dots (or pixels). The spacing of these
pixels can give the illusion of shades or tone. Increasing the spacing of
dots lightens the shade so that it tends towards white (colour of the page).
Moiré pattern
This is an undesirable pattern that occurs due to pixel (or) dot placement.
The eye is able to pick up repetitive patterns that exist within an image.
These can be eliminated during print by careful selection of screen angles.
Pixel
This is the smallest addressable dot or PICture ELement. This has been
abbreviated as PIXEL rather than PICEL.
English
Highlight
This is the lightest part of an image. In the extreme, this would be white.
Hue
Hue identifies the colour and is the property that differentiates blue from
red and red from yellow etc.
Indexed colour
Colour pixels are represented by 8-bits. This gives the possibility of 256
(28) colours which are contained in a lookup table.
Lightness
This describes the intensity of a colour and determines whether a colour
is closer to black or white.
Colour Guide 21
Primary colour
All colours can be produced by mixing a limited set of colours. There are
two different sets of primary colours associated with the video and
printing industries:
Additive primaries
Red, Green and Blue (RGB) are the additive primaries and the basis for
forming other colours in displays such as computer monitors or television.
Subtractive primary
Cyan, Magenta and Yellow (CMY) are the subtractive primaries and are
the basis for inks used in colour printing. Colour is produced because
inks are designed to absorb certain wavelengths of light and transmit
others.
Registration
This describes the alignment of the various colours when printing. As
each of the process primaries are specified by their own plate and printed
individually, it is important that the ink is placed in precise locations or
colours will not align to produce the desired result.
Saturation
This property indicates whether the colour will be perceived as dull or
vivid. A vibrant red is more saturated than brick red for example.
Secondary colour
Mixing two primary colours in equal amounts will produce a secondary
colour.
Spot colour
These are additional colours used in printing that are not a part of the
process ink set and specified individually. These colours are required
when the end result is of paramount importance (such as within a corporate
logo) as there is a substantial increase in cost. A separate plate is also
required.
22 OKIPAGE 8c Plus
Index
A
additive primary ........................... 8
B
brightness ................................... 19
C
cluster-dot screening .................. 19
CMYK model ............................... 9
colour
adjustments ............................. 15
complements ............................ 9
manual adjustment ................. 18
mapping .................................. 19
models ....................................12
neutral ....................................... 9
perception ................................. 5
print colour swatch ................. 17
printing ................................... 14
problems with .........................11
registration ............................. 14
colour management system ........ 19
colour matching
systems on OKIPAGE 8c Plus . 17
colour matching systems ............ 11
colour models .............................19
colour separations ......................20
colour space ................................20
colour wheel ............................... 10
colourants ...................................20
D
density ........................................20
dithering .....................................20
dot gain ....................................... 20
E
electromagnetic spectrum ............6
G
gamut .................................. 11, 19
glossary ....................................... 19
grayscale ..................................... 21
H
halftone
setting on OKIPAGE 8c Plus ..17
halftoning ...................................21
highlight .....................................21
hue ...................................... 10, 21
I
indexed colour ...........................21
L
light source ................................... 5
lightness ............................. 12, 21
M
Moiré pattern .............................. 21
O
object ............................................ 5
observer ........................................ 5
P
pixel ............................................ 21
primary colour ...................... 7, 19
additive primaries ...................21
subtractive primaries .............. 21
print mode
option on OKIPAGE 8c Plus ... 16
printer driver ...............................16
English
Colour Guide 23
R
registration ................................. 22
S
saturation .................................... 22
secondary colour .................. 7, 22
spot colour .................................. 22
subtractive primary ....................... 8
24 OKIPAGE 8c Plus
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