Oki 8c Plus - Manual (Page 21)

Colour Guide 21
English
Grayscale
Differing shades of grey ranging from black to white. Eight bits of data
will produce (2
8 ) 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).
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
(2
8 ) 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.
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.
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.