Section 7 – Calibration
RadianceXD/XE
rev 06/21/11
30
•
Check your results with a realistic image. Some displays can be adjusted so that the 96 IRE bar is
visible but the image does not look it’s best due to a too-high contrast setting. In this case adjust
the display’s contrast control to reduce the maximum brightness until the video image looks good.
•
If either the 4 IRE and/or 96 IRE bars cannot be made visible after adjusting the controls, check
that the appropriate Lumagen output level (Video or PC) has been selected. The command is:
MENU
→
→
→
→
Output
→
→
→
→
Styles
→
→
→
→
[Style]
→
→
→
→
HDMI Format
→
→
→
→
Type
→
→
→
→
(PC, Video)
Color Management
The Radiance Color Management System (CMS) controls are used to calibrate display grayscale tracking,
gamma plus primary, and secondary, colors. The use of these controls requires advanced knowledge and
special equipment. We suggest that a qualified video technician be hired to do this calibration.
Calibrate 100 IRE white to D65 using the display’s controls
•
Note that Lumagen recommends that a qualified video technician be hired to calibrate grayscale.
•
It is best to calibrate the 100% white point color-of-gray in the display when possible. If the
display has a custom grayscale control, calibrate the 100% white point as described below.
Otherwise skip this step.
•
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 select the 100 IRE Window
test pattern. The command is:
MENU
→
→
→
→
Other
→
→
→
→
Test Pattern
→
→
→
→
Reference
→
→
→
→
OK
•
Adjust the color temperature of 100% white to D65 using the display custom grayscale calibration
controls. Note that, if the color gamut is to be calibrated, the selected color temperature in the
display should be one where the red, green and blue primaries are outside the CIE color triangle
for the desired color space.
•
If the display 100% White Point cannot be calibrated, select a “Color Mode” in the display that
gives a result for the 100% White Point that is close to the D65 specification. The use the Radiance
CMS “White” calibration to adjust the 100% White Point.
•
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 Radiance primary color gamut
•
Many digital displays have over-saturated primaries. The Radiance CMS controls allow the
characteristics of the primary and secondary colors to be corrected. 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 typical CRT
based displays) they cannot be corrected.
•
Note that if needed in the Radiance, the 100% white point should be adjusted using the gamut
white-point calibration rather than the grayscale calibration menu.
•
The Radiance menu mode must be set to “Service mode” to make changes. The command is:
MENU
→
→
→
→
Other
→
→
→
→
Menu control
→
→
→
→
Menu mode
→
→
→
→
Service mode
→
→
→
→
OK
•
The gamut calibration command usage is described in a Tech Tip on the Lumagen support web
page. The command is:
MENU
→
→
→
→
Output
→
→
→
→
CMS’s
→
→
→
→
[CMS]
→
→
→
→
Color Gamut
→
→
→
→
OK
Calibrate Radiance 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 a color
temperature close to D65, and the 100 IRE white point should be calibrated using the display
controls or the Radiance gamut white-point, if feasible. Then the Lumagen parametric grayscale
controls should be used to calibrate the other gray levels.