Hi Mark.
It is possible to change the default page colour from white to another colour.
Click on File>Settings>Flipchart>Default page colour.
For example, if you have 4 flipchart pages already in white, once you change this it won't overwrite the current 4 pages but each next page will change to the new default page colour.
I hope this information helps.
Adam
Promethean Technical Support
(Case 00458195)