INPUT CLIPS
Background: clip over which the rainbow is to appear.
Atmosphere: can be used as an atmosphere clip controlling the areas in which the
rainbow will appear. If you use something like a cloud image the bows will be thinned by
the luminosity of this clip. Or you can use it to mask out parts of the rainbow.
PRIMARY BOW
These controls relate to the appearance of the primary, or main rainbow.
Brightness (Min: 0.0 Max: 200.0 Default: 100.0)
The relative brightness of the primary bow.
Density (Min: 0.0 Max: 100.0 Default: 100.0)
Sets the density of the rainbow. This controls the extent to which it
obscures the background image.
Fade Off (Default: Linear)
Hermite=0
Linear=1
No Fade=2
How the bow will fade off near the start and end angle positions.
Atmosphere (Default: Off)
Off=0: no atmosphere.
On=1: the atmosphere input clip is used to modulate the intensity of
the rainbow.
Vignette (Min: 0.0 Max: 1000.0 Default: 0.0)
Setting this to more than 0.0 will cause the background image to be attenuated
or darkened (cumulatively) beyond each successive bow order.
This gives a nice artistic effect.
GEOMETRY
Center XY (Default: above center)
Radius (Min: 0.0 Max: 500.0 Default: 40.0)
Defines the primary bow position and size.
BoWidth (Min: 1.0 Max: 100.0 Default: 8.0)
Sets the width of the primary (first order) bow.
End Width (Min: 1.0 Max: 500.0 Default: 0.0)
Controls the relative width of the rightmost near vertical part of the bow
compared to the width of the bow at its highest point. The higher this
number, the relatively wider the bow will get as it reaches the ground.
Start Angle (Min: 0.0 Max: 360.0 Default: 0.0)
The angle (measured in degrees from zero at due East) at which the
bow will start.
End Angle (Min: 0.0 Max: 360.0 Default: 180.0)
The angle at which the bow will end.
Deletion Angle(Min: 0.0 Max: 180.0 Default: 10.0)
The angle adjacent to the start and end angles within which the
bows brightness and intensity will decline to zero.
SECONDARY BOWS
Number (Min: 1 Max: 10 Default: 3)
Sets the number of ``orders'' or rainbows. Usually, you only see the first
order rainbow in real life. You can sometimes see the second order
(higher and more spread out than the first, and with the order of the
colors reversed). There can be higher orders, too, but they are almost
always too dim to see. Each order comes from light being reflected a
different number of times within the raindrops before emerging to be
viewed by the observer --- the first order comes from 1 reflection,
the second from 2, and so on.
Width Scale (Min: 50.0 Max: 500.0 Default: 75.0)
Sets the width of higher order bows as a scaling of the preceding
order bow width. If less than 100.0, bows will get narrower as their
order increases. If greater than 100.0, they will get wider.
This latter is the behaviour observer in real life, but the default
is for them to get narrower for artistic reasons.
Gap Scale (Min: 100.00 Max: 2000.0 Default: 200.0)
Sets the gap to the next bow order as a scale of the bow width.
Brightness Scale (Min: 0.0 Max: 100.0 Default: 30.0)
Controls the relative brightness and density of higher order bows.
This is a scaling of the brightness and density of the preceding bow order.