This HSE slide show explains the importance of Tyndall lamp assessments in a spray paint application. A Tyndall lamp uses the sunlight effect to illuminate invisible particles that you cannot see under normal circumstances.
The tyndall assessment is an important element of an LEV Through Examination and Test. The usefulness of a Tyndall lamp is not confined to spray painting applications. It is also useful in determining the effectiveness of hoods handling other substances (e.g. wood dusts, slate dusts etc).