Hand- Painted Racing Numbers

[TomoHawk]

I was watching an old 50s racing movie, and i it I saw a guy painting a racecar number on the big white  roundel using a large (round) paintbrush and black paint.  Is that how they actually did it back then?  What kind of paint was used, and how did they remove or change the number for the next race without ruining the white roundels?

 

I did a little Internet research, and found some references that  when you go to places like Silverstone, Spa, Targa Florio, they had an official number-painter or signwriter, so all the numbers looked about the same. There was also a few mentions of black "tyre paint" which sounds like black plasti-Dip, which should be removeable.

 

The white roundel should not be a big deal today on a vintage sportscar, as it would be (to police) on a modern tuner.  So you could paint the roundels  on, and either paint the number or apply adhesive ones as needed.

 

If there is  official jargon for this, please inform me, and thanks for the discussion.