The program's "virtual camera" works in a manner similar to actual point-and-shoot cameras. It automatically calculates the correct "exposure" for the lighting situation and produces a view with infinite depth of field (i.e. everything is in focus). However if, in exceptional circumstances, you want to brighten or darken a rendering, you can use the Image Brightness option to manually override the automatic exposure. Brightness can be increased or decreased.
To adjust image brightness:
Select View
> 3DTrueView > 3DTrueView Options, or click the 3DTrueView
Options button on the 3DTrueView toolbar.
In the Program Settings dialog, select the Rendering tab.
Specify the amount you want to increase or decrease the brightness in the Image Brightness edit box, or use the arrow buttons to scroll up or down. A positive value increases the brightness, while a negative values decreases it.
Click OK.