Formatting All-Day Events on Monthly Calendar

How do I change the color (shading) on my All-Day Events? Unlike the timed events (which appear clearly in black ink on the white background page), the All-Day Events all appear in white print with gray shading on the computer screen. When printing the monthly calendar either in black & white (or color) the All-Day Events appear in black print with gray shading (very difficult to read). I don't see any text or event formatting menu option in the iCal application (yet the iCal 101 tutorial shows events in different colors. How do I do that?