This part of ISO 3233 describes a procedure for determining the non-volatile matter by volume, NVV, of coating materials and related products by measuring the density of a dried coating for any specified temperature range and period of drying or curing. This method determines the non-volatile matter immediately after application. Using the non-volatile matter by volume results obtained in accordance with this part of ISO 3233, it is possible to calculate the spreading rate of coating materials. The method specified in this part of ISO 3233 is the preferred method for air-drying materials. Its use for other materials still has to be tested. This part of ISO 3233 is not applicable to coating materials in which the critical pigment volume concentration is exceeded.