Open as PDF
32 __________________________________________________________Barco - DCMS - User Manual
Running the DCMS application
The three input text fields ‘x’, ‘y’ and ‘Y’ are disabled as long as the check box
‘Follow white point and gamma’ is selected. This means that changing white
point, gamma or brightness settings will influence the mid gray point. The color
coordinates will match those of the white point and the luminance is calculated
from the gamma and the brightness.
Uncheck the ‘Follow white point and gamma’ will allow you to set the desired mid
grey point if this should differ from the white point.
Figure 14: Match of white and mid gray color
Figure 15: Mismatch of white and gray color
Human vision has a non-linear perception of changes in luminance (light
intensity). This non-linearity can be characterized by a power-law expression.
This power-law is used in display technologies to map the number of possible
gradations in luminance to a more perceptually uniform space. The Greek letter
gamma is the power in this power-law expression. Typical gamma values for
displays range from 1.8 to 2.8. The pictures below illustrate changes in gamma.
Figure 16: The gamma power-law