Datacolor User to User Support Group.

Hi newbie here
I am using spyder2express for the first time to calibrate my monitor 
for printing photographs to my Epson R800 printer.My question is as 
follows what is the best room lighting to use with the calibration is 
it ok to have the room light on or is it best to use daylight.The room 
I am in at present is not vety bright,in fact could be described as 
fairly dark with the light off.Even with the light on it is not all 
that bright as using energy lamps. Any suggestions would be much 
appreciated.
Mick