For over 40 yrs. But in the 1950's, students began to wear gowns that were their school's colors. I am going to give you a direct link to the American Council on Education - Their Academic Costume Code and Ceremony Guide. This is 14 pages when printed out. Also, visit E. R. Moore Company, makers of cap and gowns.
Graduation ceremonies can be a solemn occasion or time for celebration.
Some students really care about their graduation night and it's memories. Others could care less and can't wait to exit school and go on. Some return regularly to class reunions. Others never attend. Many successful people today say they had a hard time in school.