Abstract: Pigment of the general formula:f.Het (I)where F is the cation of a cationic dye which has an absorption maximum at >700 nm and may or may not contain anionic groups and Het is an anion of a heteropolyacid based on tungsten, molybdenum, vanadium or a mixture of these with phosphorus, silicon, cobalt, aluminum, manganese, chromium, nickel or a mixture of these or a copper (I)-hexacyanoferrate(II) anion, are superior to the known IR dyes in terms of thermal stability and photostability, and give optical recording media having superior properties, such as a high signal/noise ratio.

Abstract: A vat dye based on monobromofluoranthene is prepared by a process in which monobromofluoranthene which contains no more than 7% of dibromofluoranthene is reacted with 1-amino-4-benzoylaminoanthraquinone, the reaction product is condensed at from 50.degree. to 70.degree. C. in 83-88% strength sulfuric acid to give the carbazole compound, and the latter is then further brominated to a bromine content of from 20 to 23% by weight.The dyes obtained by the novel process are very useful for dyeing cotton.

Abstract: Pigments of the general formulaF.multidot.Het (I)where F is the cation of a cationic dye which has an absorption maximum at >700 nm and may or may not contain anionic groups and Het is an anion of a heteropolyacid based on tungsten, molybdenum, vanadium or a mixture of these with phosphorus, silicon, cobalt, aluminum, manganese, chromium, nickel or a mixture of these or a copper(I)-hexacyanoferrate(II) anion, are superior to the known IR dyes in terms of thermal stability and photostability, and give optical recording media having superior properties, such as a high signal/noise ratio.

Abstract: Pigments of the general formulaF.multidot.Het (I).where F is the cation of a cationic dye which has an absorption maximum at >700 nm and may or may not contain anionic groups and Het is an anion of a heteropolyacid based on tungsten, molybdenum, vanadium or a mixture of these with phosphorus, silicon, cobalt, aluminum, manganese, chromium, nickel or a mixture of these or a copper(I)-hexacyanoferrate(II) anion, are superior to the known IR dyes in terms of thermal stability and photostability, and give optical recording media having superior properties, such as a high signal/noise ratio.