17
This variable is known as metemerism and essentially
points to the fact that an optimum digital inkjet colour
proof system must deliver 4,000-6,000 colours in a
gamut to match offset printing. A seemingly short order
if you consider that the human eye can distinguish up to
ten million colours in its gamut. But still a significantly
tall technology order, even given the recent advances in
inkjet.
This is where ICC profiling comes in. The International
Colour Consortium (ICC) was established in 1993 by
eight industry vendors for the purpose of creating,
promoting and encouraging the standardization and
evolution of an open, vendor-neutral, cross-platform
colour management system architecture and
components. The resultant ICC profile format essentially
provides a cross-platform device profile format that can
be used to translate
colour data created on one
device into another
device's native colour
space. Furthermore,
embedded ICC profiles
allow users to
‘transparently’ move
colour data between
different computers,
networks and even
operating systems without
having to worry if the
necessary profiles are
present on the destination
systems.
ICC profiles permit tremendous flexibility
to both users and vendors. For example,
it allows users to be sure that their
image will retain its colour fidelity when
moved between systems and
applications, assuming the new system is
capable of reproducing all the original
colours. While it allows an inkjet printer
manufacturer to create a single profile
for multiple operating systems.
The specification divides colour devices
into three broad classifications: input
devices, display devices and output
devices. For each device class, a series of
base algorithmic models are described
which perform the transformation
between colour spaces. These models
provide a range of colour quality and
performance results which provide
different trade-offs in memory footprint,
performance and image quality. The
device profiles obtain their openness by
using a well-defined reference colour
space and by being capable of being
interpreted by any ICC operating system
or application that is compliant with the
specification.
Colour in Profile
B
EFORE EVEN GETTING INTO PRINTED BEHAVIOURAL QUIRKS
CAUSED BY THE USE OF DIFFERENT INKS ON DIFFERENT PAPERS
,
OR HOW THE SAME INKJET DEVICE MAKE AND MODEL CAN
PERFORM DIFFERENTLY UNDER CHANGING ENVIRONMENTAL
CONDITIONS
,
LIKE DIFFERING HUMIDITY LEVELS OR
TEMPERATURES
,
IT IS WORTH NOTING TOO THAT COLOURS LOOK
DIFFERENT UNDER VARYING VIEWING CONDITIONS
.
