Engoben

1. This chapter does not cover: (a) separate chemically defined elements or compounds (except those of heading 3203 or 3204, inorganic products of a kind used as luminophores (heading 3206), glass obtained from fused quartz or other fused silica in the forms provided for in heading 3207, and also dyes and other colouring matter put up in forms or packings for retail sale, of heading 3212); (b) tannates or other tannin derivatives of products of headings 2936 to 2939, 2941 or 3501 to 3504; (c) mastics of asphalt or other bituminous mastics (heading 2715). 2. Heading 3204 includes mixtures of stabilised diazonium salts and couplers for the production of azo dyes. 3. Headings 3203, 3204, 3205 and 3206 apply also to preparations based on colouring matter (including in the case of heading 3206, colouring pigments of heading 2530 or Chapter 28, metal flakes and metal powders), of a kind used for colouring any material or used as ingredients in the manufacture of colouring preparations. The headings do not apply, however, to pigments dispersed in non-aqueous media, in liquid or paste form, of a kind used in the manufacture of paints, including enamels (heading 3212), or to other preparations of headings 3207, 3208, 3209, 3210, 3212, 3213 or 3215.