An external proton beam from the Lucas Heights 3 MV accelerator has been used for demonstration measurements on pigments in acrylic and water color paintings. Proton-induced x-ray emission is very sensitive to elements from silicon to zirconium, being able to detect the presence of < 10 ppm in thick samples in favorable cases. This is the range of elements present in many inorganic pigments, each of which has a typical elemental composition. Pigment identification can be carried out, nondestructively, by positioning various parts of a painting in front of the proton beam. Less than one minute irradiation is usually sufficient (with a 1-10 nA proton beam) to obtain an x-ray spectrum with good statistics for major elements. Even faint brush strokes can often be identified, especially if they contain an element heavier than the major elements in the ground. The measurements are sensitive to approximately 20 mum depth of material and the beam diameter can be varied from < 1mm to 10mm according to the requirements. -- AATA