The chemistry of ketone resins (Polycyclohexanone resins) and the stability and flexibility of varnishes based on ketone resins and reduced ketone resins are discussed. The synthetis of a product with increased stability and flexibility, a derivative of Laropol K80 (BASF), is described. The stability of the product is compared with other commercially available resins which have potential for picture varnishing purposes. Experimental methods are outlined, suppliers are listed, and references are provided. Figures.