This document (ISO 6504-3) specifies methods for determining the hiding power given by paint coats of white or light colours of tristimulus values Y and Y10 greater than 25, applied to a black and white chart, or to a colourless transparent foil. In the latter case the tristimulus values Y and Y10 are measured over black and white panels. Subsequently, the hiding power is calculated from these tristimulus values. This document specifies also a simple method for calculating the spreading rate for paints with a volatile matter content with low evaporation speed, e.g. coatings for interior walls and ceilings as specified in EN 13300.