Display Calibration Utility
LCD display in Mac OS X
The following tutorial
describes the process of
calibrating an Apple LCD display using
the Apple built-in Display Calibrator
Assistant Utility. Before beginning the process of
calibrating your LCD display and to make it easier for yourself I
recommend that you use a mid grey desktop background. You can change
back to your favourite background image/color when the calibration
process is completed.
From Mac OS X System Preferences panel open
Ensure you display is set to the
Native resolution (LCD's should always
be set to the native resolution otherwise images will appear
Ensure Colors is set to Millions
Set the Brightness
slider to your preferred value (the Apple
default is approximately 60%,
although a slightly brighter level might be necessary on aging
Note: the screenshots used
in this tutorial are based on the version of Display Calibrator
shipped with Mac OSX 10.4 (Tiger), but they should still be valid for
Choose the Color tab
Search the list of Display
Profiles for one that matches your display and select it. In
truth this step shouldn't be required since the calibration utility
automatically picks up the necessary data from the display via the
Press the Calibrate
if after calibrating your display you find that it appears to revert
to the uncalibrated state then repeat the step outlined above but
this time select the new calibration profile. Very often this problem
arises after the computer wakes from sleep mode and is especially
prevalent with the MacBook and MacBook Pro range. It's actually a bug in the
Operating System that for one reason or another Apple seems unable or
unwilling to fix.
Native Gamma of the Display
The checklist down the left side of the Display
Calibrator Assistant dialog is only a guide and not all steps will be
applicable to all display types. The following
screenshot shows the first of five steps used to determine the
native gamma of the display. This arrangement is an improvement on
the old scheme used by Apple and was developed because they recognised
the difficulty many users had in adjusting the blue channel gamma. In
each step you will be adjusting the Brightness and Tint
thus obtaining much finer control of the gamma curves.
Begin by adjusting the Brightness
slider (1) vertically so that the
apple symbol blends with the background.
Next using the Tint slider (2)
trim out any color imbalance that may be present. You may need to
readjust the left hand brightness slider a little more after this step.
It's helpful to squint when
trying to blend the inner and outer shapes.
- Native Gamma - Brightness and Tint
The remaining four steps are basically a repeat of the first but
effect other parts of the gamma curve. You should follow the instructions
given by Apple in the dialogs.
Step 2 - Fine-tuning the Mid-tone Response
Step 3 - Fine-tuning the 3/4-tone Response
Setting the Target Gamma
Once the native gamma has been determined it only
remains for you to decide on your preferred target Gamma. For many
years the standard gamma setting for Macs was 1.8. Compared to gamma
2.2 a setting of 1.8 will appear quite bright. In other words gamma 2.2
will appear darker and more contrasty than what many long time Mac
users are used to. If you don't have a need (or love affair) with gamma
1.8 I recommend that you choose gamma 2.2. The majority of
displays (CRT and LCD) will have a Native gamma somewhere
between 2.0 and 2.2 so choosing a lesser value requires a fair
amount of adjustment on the part of the graphics card LUT, and will tend
to cause banding or posterisation.
Figure 4 - Setting the Target Gamma
Choosing the White Point
High-end LCD's such as those from Apple
tend to be factory set to a value of around 6500oK
(i.e. their Native White Point is 6500oK) and
so it only remains for the user to check the box labeled Use native
white point. However, it is worth mentioning that as the display
ages the backlight will slowly begin to discolor. At time of writing
this tutorial my display is measuring around 6350oK
which is well within the margin of error when using the human eye as a
measuring device (see footnote).
Figure 5 - Typical LCD White Point Setting
Naming and Saving the Display
The final step requires that you give the display
profile a name. Pressing the Create button will crate the new
display profile and saves it to the appropriate folder for use by the
system. Photoshop will automatically read and use this display profile
until it is superseded or deleted.
6 - Name and Save the Profile
Figure 7 - Summary of calibration results
Whilst this tutorial used the Apple Display Calibrator Utility
many have found a small shareware application called
SuperCal to be much better.
I haven't used it but have been told by readers of this site that it
delivers superior results to Apple's Display Calibrator.
Visual display calibration can get you in the right
ballpark, but it comes a very poor second to proper hardware based
calibration. This is especially true as the display ages. Many who make
the transition find the difference between software only and hardware
based systems to be quite significant, and the initial cash outlay for
the hardware is quickly recovered through a reduction in poor
screen-to-print matches. The following hardware based
solutions are worth investigating:
Datacolor Spyder3PRO and X-rite
Photo i1-Display 2.