Barco DP2K SLP Series, Service Manual

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R5906848 /04 DP2K SLP Series 169
Tip: Put in the MCGD file name the type of projection mode (2D or External 3D) and the aspect ratio
(FLAT, SCOPE).
5. Map the MCGD file with the TCGD file. Use for that the Communicator. Go to Installation > Color calibration >
Select target colors . For detailed instructions see user guide of the Communicator.
6. In addition you can check if the corrected colors comply. Use therefore the Communicator. Go to Installation >
Color calibration > Verify corrected colors . For detailed instructions see user guide of the Communicator.
15.2 Light measurements for SmartCare contracts
15.2.1 Screen gain measuring
About screen gain
Fig. A and B illustrate the concept of gain.
A B C
Image 15-3
A Gain 1 (perfect diffuse)
B Higher gain screen (e.g. 1.8)
C Higher gain screen (e.g. 1.8)
In Image 15-3, reference A , the incident light beam (red arrow) diffuses from a gain 1 screen uniformly in all
directions. The resulting screen brightness (in fL or cd/m2) is L
a
.
In Image 15-3, reference B , the screens reflects a higher portion of the light in the direction of the incident
light, at the expense of the light under angles. The resulting screen brightness in the perpendicular direction is
L
b
.
Screen gain is defined as the ratio of the reflected luminance produced by a projector beam of white light
falling onto the screen surface, compared with the reflected luminance of a reference standard with gain of
1.0. The screen gain of the second screen is L
b
/L
a
.
Image 15-3, reference C illustrates the case when the incident light on a gain screen is not perpendicular. In
that case, most of the light is reflected in the opposite direction – similar to what a mirror would do.
Typically the reference standard for gain measurement is a tile of magnesium carbonate (gain 1.0) which can
be obtained from screen manufacturers. For convenience, white cartridge paper can be used as a reference
standard. It has a gain value of approximately 0.9. Realistic white screens have a gain value of around 0.95.
About Hotspot
Higher gain screens typically experience an effect called ‘ hotspot ’ . The hotspot is not localized, as it depends
on the viewer position versus the projector, so it typically ‘ follows the viewer ’ as people walk around. Every
viewer has his or her own hospot position. In Image 15-4 reference B you see the impression of the hotspot if
you have moved to the left of the center.
Color calibration & Light measurements