The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Having thus described the origin and uses of the pigment, we now come to the question, what is lithopone? It is, in short, a chemical compound usually consisting of 30.5 per cent zinc sulphide, 1.5 per cent zinc oxide and 68 per cent barium sulphate, but these proportions vary slightly in the different makes. Lithopone of this composition is sold as the highest grade, either as red seal or green seal, as it best suits the idea of the manufacturer. Many manufacturers, especially in Europe, sell and also export other brands under other seals, containing 24, 20, 18 and as little as 12 per cent of zinc sulphide with very small percentages of zinc oxide, the balance being usually barium sulphate, but sometimes certain portions of China clay or gypsum (calcium sulphate) or whiting (calcium carbonate). Such brands are not a chemical compound, but mechanical mixtures of the chemically compounded lithopone and the admixtures referred to.

Edelweiss, 14.5 per cent zinc sulphide, 84 per cent barium sulphate, 1.5 per cent carbonate of lime.

Titanium dioxide holds exceptional significance as a white pigment due to its superior scattering capabilities, remarkable chemical stability, and non-toxic nature. Among all white pigments, it surpasses others in terms of its ability to scatter light effectively. Consequently, titanium dioxide stands as the most significant inorganic pigment, accounting for the highest quantity in usage. The majority part of the global production of ilmenite and rutile is dedicated to the production of TiO2 pigments. The remaining portion is utilized for the manufacturing of titanium metal and in the production of welding electrodes.