The ketone aldehyde resins on which the invention is based possess a low water content and are therefore suitable for use in high-grade coating materials such as 2-component polyurethane varnishes, for example. Furthermore, as a result of theprocess, the resins are soluble in alcoholic and aromatic solvents, and so are suitable for applications in which, for example, long-oil alkyd resins are used. As noted above, the water content of the resin is less than 0.4% by weight. In preferred embodiments, the water content may be less than 0.3, 0.2 or 0.1% by weight. The resins of the invention have only a slight tendency toward yellowing during thermal exposure. Moreover, the products of the invention possess a high nonvolatiles content and are therefore suitable for low-VOC applications.