iBook Screen dimming

[David Crump]

Is there any way to stop the iBook's screen from dimming after a period 
of inactivity?  I have an iBook SE 466MHz with OS X 10.1.5
I have checked out the energy saver control panel and all I see are 
options to stop it from going to sleep, but nothing for the dimming 
feature.  I want to run a slide show on the iBook for an afternoon and 
want the screen to remain bright the whole time.  Thanks for any help.
Dave.