Way back in the 80's and 90's. I was involved with another sign company known as "Graphics International"
Together we produced some of the first vehicle illustrations ever done. In the beginning, all of the bus graphics were hand painted onto the buses. Sometimes taking a couple of weeks to finish. But demand grew quickly for what we were doing, and so a process of printing the artwork was developed. And then we could provide "wraps" for transit authorities all over the country.