Of the numerous techniques available for imparting color to both interior and exterior concrete surfaces, painting is unquestionably the easiest and, if consideration is given only to initial cost, probably the cheapest. Paints not only provide the widest possible selection of colors, but some of them, especially the cement and latex emulsion formulations, are astonishingly effective in concealing minor surface imperfections. Cement-base paints often perform excellently under exposure conditions which cause other types of paint to deteriorate. Their durability is outstanding and they do not conceal the natural texture of the concrete. Cement-base paints also mask minor surface imperfections and help prevent seepage. They can be applied to damp concrete surfaces and to surfaces which will be damp frequently. Their resistance to alkaline conditions and freeze-thaw cycles is quite good. Oil-based paints are formulated of a drying oil such as linseed oil, thinners, pigments, and driers. They initially have a glossy surface, but in time they begin to chalk, shedding dirt and mildew. Inevitably the paint erodes until eventually it is no longer thick enough to provide adequate protection. The rate of chalking is increased by intense sunshine and rainfall. Varnish-base paints generally contain resins, oils, solvents, driers, thinners, and pigments. They are available in types that provide flat, egg-shell, semi-gloss, and full gloss finishes. The gloss and enamel types should be used where frequent washing will be necessary or where exposure to water is expected. Although varnish-base paints provide excellent resistance to water falling on concrete, they will blister and peel if water migrates to the surface from within the concrete. Types of coatings have been introduced in the 1960's. They produce a high gloss, ceramic-like surface, and are available in a wide range of colors. They produce a surface texture different fro+m that of the raw concrete. There are two types of coatings. Urethane coatings are most frequently used for floors and other applications. They have gained considerable popularity for storage tanks and other applications which expose the surface to extreme chemical contamination. Neoprene coatings provide increased resistance to chemicals and water.