Automotive tinting specifics
Soap Spray
Soap spray is the informal name for the application solution used to wet glass and film during installation; the precise formulation matters less than the cleanliness of the water.
Workshops sometimes refer to the application solution as "soap spray" because of its main visible characteristic — a mild soap dissolved in water.
The important controls are water purity (de-ionised), surfactant choice (mild, residue-free), and absence of contaminants. A surprising amount of finish quality depends on a clean spray and clean spray bottles.
The fact that some workshops re-use spray bottles between jobs is one of those small details that signals a quality gap. Infratint mixes fresh solution for every install and uses dedicated bottles for each chemistry.