Accurately calibrating and characterising the monitor is the probably
the most important aspect of the colour-managed workflow. The aim is to
calibrate and characterise the monitor so that we eliminate unwanted
colour casts and so obtain the best possible display environment for
editing our images. We characterise the monitor by means of creating an
ICC device profile, which is simply a data file that includes a
description of the monitorsí colour handling characteristics. The profile
will then be used by Photoshop to compensate for the colour limitations
of the monitor. Photoshop automatically optimises the display of images
by carrying out an on-the-fly conversion between the image/document
profile (e.g. Adobe RGB, sRGB, ColorMatch) and the monitor profile. This
conversion does not alter the actual image in any way.
Note: Adobe no longer supply Adobe Gamma with the Mac
version of Photoshop although the Apple Display Calibrator Assistant
found within System Preferences offers similar features. A tutorial
describing the process of calibrating a display with the Apple Display
Calibrator Assistant can be found
here.
To calibrate and characterise the monitor Windows users should open
the Adobe Gamma utility or a third party alternative. For many new users
Adobe Gamma is more than sufficient and it's free.
Adobe Gamma is a Control Panel utility that can easiest be accessed
from My Computer > Control Panel. Before running Adobe Gamma, it is best
that the monitor has been switched on for at least 30 minutes. It is also
best to work in subdued lighting when calibrating a monitor using Adobe
Gamma. Another helpful tip is to set the desktop colour to grey.

Control Panel as is appears when using the Windows
Classic Theme
Step 1
When the Adobe Gamma utility is first opened you will be asked
to make a choice between the Step- by- Step (Wizard) and the
Control Panel method. It's probably easier to use the Step-by-Step
(Wizard) method.

Step 2
Using the Load button choose your monitor profile or pick one
that's close. If in doubt choose the Adobe default monitor profile
or even sRGB, it really makes little difference since all we are
doing is defining the start point.

Before progressing to the next step, be sure to give the profile a
unique description and include the date.
Step 3
Set your monitor contrast control to maximum and then adjust the
brightness control until the innermost grey square is only just visible
against the black surround. Squinting your eyes helps with this process,
as does keeping the room lighting at a low level or off.

Step 4
If you're using a manufacturer supplied profile for your specific make
and model of monitor then in all probability the Phosphors will be listed
as Custom. If this is the case leave well alone. If you don't have
a monitor profile choose either Trinitron or P22-EBU. I
keep getting asked -"how do I decide which is appropriate for my
monitor?" You can tell a Trinitron monitor by simply looking at the
display area. A Trinitron type monitor will have two faint lines running
across the display area approximately 1/4 from the top and 1/4 from the
bottom. If your monitor has these lines choose Trinitron, otherwise
choose P22-EBU.

Step 5
Begin by keeping the View Single Gamma selected. However, keep
in mind that this option ONLY allows you to adjust the relative
brightness of the monitor.
Adjust the slider until the inner grey square blends with the outer
frame, squinting slightly can help. Finally, deselect the View Single
Gamma checkbox.
