User`s manual

3. Design and functions
Barco - OverView D series - Doc-3353-2 - user's manual - Revision 05 - Aug 2005
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3.5 Filter for changing the color temperature (backdrop applications)
OverView D projection systems usually are operated at a color temperature of 6500K (daylight). In broadcast
application it might be required to have the color temperature reduced to 3200 K (reddish). Studios are often
lighted by electrically-generated tungsten light. This light has typically a color temperature of 3200K (reddish).
The cameras are adjusted to this color temperature and show "normal daylight" (6500K) images on TV. In conse-
quence incoming daylight at 6500K or projection systems generation 6500 K will appear blue. Therefore the
display wall has to be set to the same color temperator the cameras are adjusted to in order to be viewed "un-
der normal daylight conditions" on TV.
The XGA projection unit of the OverView D series can be completed by a filter changing the color temperature
from 6500K to 3200K. This filter can be put in placed when required and ensures that cameras adjusted to 3200K
record "normal daylight" when recording the display wall.
Filter active (3200K) Filter inactive (6500K) Projection unit with 3200K filter cartridge
However, the light output of the projection systems with a 3200K filter is about only 58% of the light output of
6500K systems: the lamp employed in the OverView D series have a very small share in the red part of the spec-
tral range.
Due to the field of application, this filter is only available for XGA resolution: cameras work even at lower resolu-
tion.
To compensate the reduction in light output, the projection system can be equipped with a dual lamp illumina-
tion unit which houses 2x200W VIP200 lamps.