Specifies the page background colour, in HTML only. The argument consists of three numbers from 0 to 255 separated by semicolons, for red, green and blue values respectively.
\backgroundcolour{255;255;255} \backgroundcolour{0;0;255}The first example sets the background to white, the second sets the background to blue.
Instead of using a LaTeX command, you may find it more convenient to use the equivalent .ini file setting, backgroundColour.