Go to Tools---Options---Calendar Options---
go to Background Color, change color to what you want your secondary
Calendar to be, be sure and check use selected background color on all
Calendar, after you do this exit Outlook completely, then reinitiate outlook,
then go to Background Color, change color to what you want your Primary
Calendar to be, be sure and UNcheck use selected background color on all
Calendar

hope that helps

"boback" wrote:

I can change my primary calendar in the outlook 2007 options. i want to
customize the color of my secondary calendar as well. Am I able to do that? I
dislike the grey default calendar. it does not have enough contrast in the
overlay mode.

This silly customization should be available with a right click.