Old yellow pigments may not respond to traditional analytical procedures, as in the case of natural organic dyestuffs precipitated with alum on lead carbonate as substrate. Alum converts the carbonate to sulfate, which does not give reactions expected for lead carbonate. Specific analytical procedures have to be used to detect it. The historical background (recipes for pigments from organic coloring matter) and details of analytical procedures, including also chalk, calcium sulfate and alum, are commented upon in depth -- AATA