Konica Minolta Magicolor 7300, Reference Manual

Page: 172 / 334

Color Management 164
A color printer uses the subtractive principle, which means that when we look
at a color printout, the pigments in the toners absorb portions of the white light
reflected from the white substrate. A color laser printer typically ships with
four toner cartridges: cyan, magenta, yellow and black. Mixing equal amounts
of cyan, magenta, and yellow produces black. However, since color toners
are never 100% pure, black toner is added to provide pure black. Moreover,
black toner provides a more economical way to print in black only, such as
for text.
When we talk about
printing colors, we
actually talk about
matching a design
created on a device
like a monitor, using
the additive principle
and printing these
colors on a color
printer, using the
subtractive principle.
To print correct colors
we need a module
capable of
translating
the RGB colors of the
monitor into CMY(K)
colors used by color
laser printers. This translation is device dependent. The illustration shows
such a (software) module where certain RGB values (from a monitor) are
converted into CMYK values (for a color laser printer).
There are many devices capable of producing colors, like a monitor, a color
laser printer, a digital camera, and a scanner. To avoid a multitude of
translation modules, we first need to define a standard for colors.
Since color is defined as how the human eye perceives this, we introduce the
CIE LAB color model (also called
color space , the organization of all colors of
the visible spectrum in a device-independent model). CIE is an acronym for
Commission Internationale d’Eclairage. Based on human perception, the CIE
LAB color model is most commonly used.
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