When they take to the track in a Grand Prix, Formula 1 cars are effectively some of the most expensive advertising billboard in the world. Teams will spend a fortune on the paint finish which has to be ultra light, durable and of course look great for the cameras. However, when you see the same cars testing you could often be forgiven for thinking someone had just spilled a tin of fluorescent paint all over the bodywork. 

The reason for this is that Formula 1 teams often use a special flow-visualisation paint when testing a cars aerodynamics. The “paint” is a strange combination of bright fluorescent powder and a paraffin based oil. It is applied to certain car parts just before a car takes to the test track. When the car reaches high speed, the paint moves across the body, effectively providing a graphical record of the air flow. Sometimes the paint will be translucent but the flow can be viewed under ultraviolet light, so that other teams cannot see the patterns. 

This method of collecting aerodynamic data has come to the fore more recently, as since 2021 teams are restricted in regard to the amount of wind tunnel testing they can do. 

Flow-vis is a simple and in many ways low-tech solution to a very complex problem. The aerodynamics of an F1 car are absolutely vital in terms of the downforce it creates and thus the speed that it can corner.