This
section was extracted in part from several publications including
Liquid Color Sofware and ColorVision® Spyder2PRO Studio™
2.0 documentation which are recomended calibrating tools for the
system.
Color
is something that happen in our brain. Wavelengths of light are
interpreted by biological mechanisms in the human eye and brain and
translate it to a color. This translation depend of ambient light,
the amount of alcohol or caffeine in our body, our mood and many
others factors.
In
different elements that display the same picture we see variations of
the colors that are displayed. For example a desktop CTR monitor does
not display the same colors of laptop monitor.
The
Gemewizard is a suggested solution for communicating gem color
between users, in order to be as homogenous as possible, all users
should have their monitors calibrated, until such calibration will
be performed automatically in the future.
Recognizing
the need for a simpler method of communicating color information
between devices, Hewlett-Packard and Microsoft proposed “a new
standard default color space for the Internet” in 1996. The
result, called sRGB, is a standard method of specifying color
numerically in term of varying amounts of the primary colors, red,
green and blue.
Using
this method (sRGB) special software system was created to verify the
exact position of the color in color space.
Using
a US patent-pending program, each gemstone image was digitally
recreated in 15 different cutting styles (or color rulers), making a
total database of some 150,000 images.
CRTs
monitors were almost totally dominant in 1999, but in 2004, LCD
monitors account for more than 50% of new monitor sales. This means
it’s necessary to understand how sRGB applies to an LCD
monitor, to obtain the best colors results for the Gemewizard.
In
order to do so, it’s first necessary to introduce the concept
of “gamma”.
Every
computer monitor of any kind has a non-linear input-to-intensity
response curve. As you send the monitor an increasing level of input
(for example, tell it to go steadily from black to white), the
measurable brightness increases slowly at first and then accelerates.
Gamma is a numerical value that describes how quickly the increase in
brightness occurs. An optimally calibrated CRT in its native state
(for example, the CRT in the sRGB specification) has a consistent
gamma of 2.2. (An imaginary monitor with a perfect linearity
input-to-intensity response curve would have a gamma of 1.0.) In the
process of developing the sRGB standard, Hewlett-Packard provided
studies and computations to prove that gamma 2.2 is very close to
what humans see as a uniform lightness scale for display viewing
conditions. In other words, with a gamma of 2.2, a CRT monitor seems
to go uniformly from zero brightness (black) to full brightness
(white) – even though it’s really not. Gamma 2.2 closely
matches the human visual system.
LCD
monitors have a gamma closer to 3.0. The result is that an
uncalibrated LCD’s image is too dark in the shadows and too
light in the highlights, with some color tints showing in the gray
tones. Not a good match for sRGB, and will display inaccurate color.
Methods
for calibration your LCD monitor:
There
are three fundamental methods that can be used to calibrate a
monitor, as follows:
1.
Visual calibration
2.
ICC profile-based calibration
3.
Mechanical calibration
Visual
calibration
It’s
a sophisticated but purely visual method of calibration.
Liquid
Color Sofware falls into this category.
Because
it’s visual, it’s subjective – but that’s not
necessarily bad. “Visual” doesn’t equate to
“inaccurate”. Liquid Color Sofware takes advantage of
the most accurate calibration instrument known – the human
visual system. The human visual system is a very sensitive gray-scale
detector. It’s able to detect very small variations in color
between adjacent gray areas. This fact is used to great advantage in
Liquid Color’s (patent-pending) calibration method.
Liquid
Color’s a tool to help you calibrate your LCD monitor so that
its RGB response curve closely matches the gamma 2.2 curve.
Once
an LCD monitor is calibrated with Liquid Color, it becomes an
sRGB-compliant device, ready to participate as a full-fledged member
of the Windows world.
ICC
profile-based calibration
In
1993, Apple and seven other vendors founded the
International
Color Consortium (ICC) to try to solve the problem of delivering
consistent color across applications, operating systems and devices.
Today the ICC includes 70 manufacturers and software developers. The
ICC’s approach to the problem uses “profiles”. An
ICC profile is a data file that describes the color behavior of an
input, display, or output device. The data in the file is referenced
to a device-independent color model, that is, a mathematical
representation of human color response . By always using two
profiles, one for the “from” device and one for the “to”
device, software should be able to convert color data from one device
so that it looks the same on another device.
The
problems with the “ICC profile” approach are that it’s
complex and it doesn’t provide a complete solution for all
situations. A given device can have many different profiles,
depending on the environment in which it’s used. For example, a
color printer typically has a different profile for each different
kind of paper it supports. The result is that outside of the
professional environment (graphic design, pre-press, CAD, animation,
etc.), ICC profiles are rarely used.
This
method is not significantly better than visual calibration for the
non-professional user, in fact, it’s probably worse because (a)
it’s complex, as already noted, and (b) the visual result of
any given profile may not be pleasing to the user.
Mechanical
calibration
Is
the only serious alternative for the non-professional user. It
consists of using a colorimeter (an electronic instrument that
measures on-screen colors) with appropriate software. The colorimeter
is often called a “puck” because it looks vaguely like a
hockey puck attached to a monitor screen with suction cups. Typical
prices range from $119 to $999, depending on the model.
Once
a colorimeter has measured a series of colors on the monitor, it
compares them with a device-independent standard from CIE. The
software then makes adjustments to the video card , resulting in a
gamma of 2.2.
We
recommend for this method:
Spyder2PRO™
Studio 2.0Complete calibration system for virtually all display and
presentation methods
The
ColorVision® Spyder2PRO Studio™ 2.0 now provides the
digital professional with the ultimate tool for color consistency
through virtually all display and presentation methods. Along with
the traditional CRT, LCD and notebook calibration capabilities the
new Spyder2PPRO Studio 2.0 calibration software also color corrects
your multimedia front projector with the same precision, ease-of-use
and affordability you have come to expect from the color experts at
ColorVision.
Gemewizards
is doing all the efforts to offer to you the optimal solution for
calibrating your monitor. We are exploring all the software
avaliable to integrate it with distribution of the Gemewizard.
We
are also making contacts with LCD monitors manufacturers for
obtaining a perfect monitor that automatic autocalibrate according
the ambient light and will be optimal for the Gemewizard
communications colors system.
Our
goal in Gemewizard is that all the users will see exactly the same
colors in the monitors and we are working on it.
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