Vanishing spray is a substance applied to an athletic field, to provide a temporary visual marker for use by referees for the purposes of ensuring fair-play.
Before making any markings, the referee must always shake the can to obtain a clean spray stream and then press the valve tab with the spray tip pointing down toward the field. The height to spray from may vary between 8 inches (20 cm) and 16 inches (40 cm)
The distance from the field surface will affect the width of the resulting line
From 8 inches the line will be about 3 inches wide.
From 16 inches the line will be about 6 inches wide
A spray made from a height of 16 inches will make a line about 6 inches wide
In rainy or windy conditions, it is more effective to spray more slowly from a lower height (6 inches). This way, a more consistent line is made in spite of the conditions.