Section 6 - Calibration
RadianceXD
Rev 1.0
27
Color Management
The RadianceXD has controls that are used to calibrate display grayscale tracking, gamma and primary color
correction. The use of these controls requires advanced knowledge and special equipment. We suggest that
a qualified video technician be hired to calibrate these controls.
Calibrate 100 IRE white to D65 using the display’s controls
•
It is best to calibrate the 100 IRE grayscale point in the display when possible. If the display has a
custom grayscale control, calibrate the 100 IRE point as described below. Otherwise skip this step.
•
Note again that Lumagen recommends that a qualified video technician be hired to calibrate
grayscale.
•
To calibrate the 100 IRE color-temperature point using the display’s controls, select the Lumagen
100 IRE window test pattern. This pattern has a white window on a black background. Navigate to
the Lumagen test pattern menu and then use the right-arrow key to step to the 100 IRE Window
test pattern. The command is:
MENU
→
Other
→
Test Pattern
→
Reference
→
OK
•
Adjust the color temperature of white to D65 using the display custom grayscale calibration
controls.
•
Some high-end displays have advanced calibration menus. An experienced calibrator may choose
to use some these features to do additional calibration before calibration is completed using
Lumagen controls.
Calibrate RadianceXD primary color gamut
•
Many digital displays have over-saturated primaries. The RadianceXD has a CMS (Color
Management System), which allows the position of the primary colors on a display to be moved.
Note that the primary colors can only be repositioned within the triangle that is defined by the
position of the display’s uncorrected primary colors. If a display has under saturated primary points
(such as on many CRT’s) they cannot be corrected.
•
Color gamut calibration interacts with grayscale calibration and so both commands need to be
repeated until good results for both are achieved.
•
The RadianceXD menu mode must be set to “Service mode” to make changes with this command:
MENU
→
Other
→
Menu mode
→
OK
•
The command format is:
MENU
→
Output
→
[Configs]
→
Color Mgmt
→
(Color Gamut)
→
OK
Calibrate RadianceXD grayscale and gamma
•
Grayscale and gamma should be calibrated at this point. Calibrating these parameters is an
essential part of the video calibration process. The display should have been set to the color
temperature closet to D65, and the 100 IRE white should be calibrated using the display controls, if
feasible. Then the Lumagen parametric grayscale controls should be used to calibrate the other
gray levels.
•
Color grayscale calibration interacts with gamut calibration and so both commands need to be
repeated until good results for both are achieved.
•
Grayscale calibration adjusts the “color of gray” so that the color “gray” adheres to the industry
standard D65 point, at all levels from black to white. Most HDTV’s, and projectors, are intentionally
miss-calibrated to maximize their brightness for the showroom. This calibration step is necessary to
correct this error, so the image appears as the producers intended. The command format is:
MENU
→
Output
→
Configs
→
[Config]
→
Color Mgmt
→
(Color Temp)
→
OK
•
Gamma is the response curve between black and white and also has an industry defined standard
that should be followed. Lumagen has developed a unique 11-point parametric grayscale/gamma
calibration feature, which allows both grayscale and gamma to be optimized over the entire range
from black to white, and not just at one or two points. The command format is:
MENU
→
Output
→
Configs
→
[Configs]
→
Color Mgmt
→
(Color Temp)
→
OK
