I did this job in my senior year. Because there are too many students, the general principal won't sign in person (very tired). He will ask the students to print it out on his behalf. We didn't know it at first, so we printed it in red, and several responsible persons said no, we wanted to use blue, but after printing, we couldn't change it (each person has a diploma, but if it is broken, it won't be changed), so some people will be red, and the normal ones will be blue.