This is the first of a two part general review on chemistry applied to works of art. A brief historical introduction is followed by an outline of environmental influences -- chiefly the effects of ultraviolet radiation and of relative humidity variations. A section on examination of objects of art deals briefly with various general examination methods and with the following instrumental methods (in order): gas chromatography (applied to linseed oil films); infrared spectroscopy (varnish coatings); organic mass spectrometry (gums in Indian miniature paintings); metal analysis and metallography (Chinese bronzes); X-ray diffraction; inorganic mass spectrometry (Luristan bronzes); X-ray fluorescence analysis; laser beam microprobe. A section on the treatment of art objects concentrates mainly on varnish and inpaint removal from oil paintings, and also mentions metal cleaning and paper treatment. Three diagrams, 20 halftone plates and 17 references.