I have a friend who made the rounds in the 73-75 time frame doing hotel IP graphing and commonly used a sharpie. A lot of times he used red, but it was definitely a sharpie.
As far as blue goes, I know especially with bats that black sharpie's color tended to change to a greenish tint. I believe this was the beginning of the changeover from black to blue as the preferred sharpie color.
|