The sunscreen should be applied as a large number of small droplets of approximate equal volume, distributed evenly over the whole surface of the plate. A positive displacement automatic pipette is well-suited to this purpose. To ensure the correct application rate, it is recommended that a method of validating the amount of product applied should be adopted (e.g., weighing the pipette before and after dispensing the product and / or weighing the plate before and immediately after applying the product). It is essential to limit possible product evaporation during the weighing process.