Gamma Settings - Submenu - Christie J Series User Manual

Section 3: Operation

3.6.8 Gamma Settings - Submenu

The system offers two types of gamma correction. Gamma correction can be applied to a specific source to
correct for luma encoding. This is a channel setting and reapplied every time the same signal is detected. This
is the 'Gamma' control. On the other hand the system also provides a global Gamma Correction control. The
global control offers an offset applied to all channels. This offset is used to compensate for changes in ambient
conditions such as ambient light in the room and projected material.
• Gamma Settings: The system offers two types of gamma correction. Gamma correction can be applied to a
specific source to correct for luma encoding. This is a channel setting and reapplied every time the same
signal is detected. This is the 'Gamma' control. On the other hand the system also provides a global Gamma
Correction control. The global control offers an offset applied to all channels. This offset is used to
compensate for changes in ambient conditions such as ambient light in the room and projected material.
• Gamma Correction: Applies a global offset to all gamma settings for each channel. It affects the shape of
the curve by performing a linear transform toward a gamma curve of 1.0 while the control is increasing and
likewise a linear transform toward a gamma of 3.0 as the control is decreasing. The control should only be
adjusted to compensate for ambient conditions. To correct a particular source only, use the Gamma control.
• Gamma: Select the base gamma table for a given source. Select
from one of the standard tables, a custom gamma function, or
select an arbitrary gamma table that has been downloaded to the
projector.
NOTE: A separate PC utility is needed to do this.
The 2.22 curve is a power curve typically used to encode
graphics and video sources, see Figure 3-9 Gamma Curve.
The 'standard' curve (auto setup default) is a modified 2.22
curve with a small linear section in the black that enhances the
detail in darker areas of the projected content. Typically
standard or 2.22 is used for all sources. Alternatively, if neither
default is ideal, apply a simple gamma curve by defining a custom power function and slope. Select Gamma
Function from the drop down list to enable the Gamma Function and Gamma Slope controls. For more
complex non-standard gamma curves, a user-defined curve created externally and downloaded to the
projector can be used (requires separate PC-based Arbitrary Gamma software application to create the table
and the Web UI to download it).
NOTE: If any of these special user curves have been installed, their names will appear in the Gamma Table
pull-down list.
• Gamma Function: Defines the base gamma power curve used when the base gamma table value is set to
Gamma Function. This value, combined with gamma slope setting determines the base gamma table to be
used as the custom base table. The curve is generally a power curve with a small linear segment at the bottom
defined by the slope.
• Gamma Slope: This control defines a slope to be used for the base custom gamma table for a small section
at the bottom of the curve. This slope can be used to bring in or out the low level blacks in the image. This
slope combined with the gamma function, define the custom gamma table.
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J Series 2.0, 2.4 and 3.0 kW User Manual
020-100707-03 Rev. 1 (02-2014)