Setting the Background Color
When using reflections, the background color has a strong influence on the
brightness of the objects, since many parts will reflect the background.
Thus, it often makes sense in a raytracing setup to use
a black background color.
The background color can be set in the Preferences dialog.
Click the menu entry
"Edit->Preferences".
Highlight Display->Main in the Entries list on the left.
Next, press the Edit button in the Background Color box to change the background color.
The black color is provided among the Basic colors.
Confirm your color choice by pressing OK and apply the new preferences by pressing OK
in the Preferences Dialog.
Press Next to continue.