9.5.2

356 • CHAPTER 7
OBJECTS MENU • LIGHTING • 357
To create a dark, dusty light, on the Visibility tab, set Brightness to a low value.
In principle, you can use dust in conjunction with particles to create realistic re and smoke.
Dithering
This produces irregularities in the visible light, which can help to prevent unwanted banding or
contouring in the visible light source.
With certain light source combinations, such as visible lights that overlap, you
may nd that the 24-bit picture depth of your output device is insufcient and
it may display color gradients in large steps. This display problem is known as
‘contouring’. To avoid this problem, use the Dithering option to give the visible
light irregularity and help to smooth the color graduations.
Use Gradient
A visible light’s gradient. Left: Omni light; right: Spot light.