File photo/Arizona Daily Wildcat For the uninitiated, painting 'A' Mountain can prove to be quite messy. In a photo from last year's excursion up Sentinel Peak, freshman take a break after painting themselves and the mountain.

About 100 freshmen wielding brushes and blue paint will tackle and paint part of the giant "A" tomorrow morning in the Tucson Mountains west of campus.

The 80-year-old university tradition, called A-Day, will begin at 8 a.m. when students climb into three buses, drive to Sentinel Peak and spend the next few hours painting one third of the "A" blue.

The event is organized by the Blue Key National Honor Fraternity every year to welcome freshmen to the UA and teach them important university traditions, said Jim Drnek, Blue Key adviser.

Students will be given a quick history lesson on the UA fight song "Bear Down, Arizona" and how the "A" was created before the main activity begins, said Garrett Munro, Blue Key president.

UA students built the "A" itself - which is made of rock and is 106 feet long and 70 feet wide - in 1915 on the side of Sentinel Peak in the Tucson Mountains, according to the UA Web site "Through Our Parents' Eyes."

Since then the peak has been called "A" Mountain and was whitewashed every year on A-Day. The color scheme changed after the start of the Iraq war, however, when the Tucson city council voted to repaint it with three stripes of red, white and blue until the war ended, Drnek said.

Though other groups in Tucson occasionally paint the "A" illegally, Blue Key is authorized to hold A-Day and works closely with the Tucson Department of Parks and Recreation, which owns the land, Drnek said.

The Associated Students of the University of Arizona Senate voted at a meeting last month to fund about $650 for the event to pay for two buses to cart students to and from the mountain.

The Freshman Class Council paid for the third bus, said Munro, a business management senior.

Two freshmen will be selected to be A-Day king and queen based on outstanding academics and involvement, and the chosen royalty will be announced tomorrow morning and before the UA football game against Purdue, Munro said.