The North Atlantic preservation Center maintains 400 historic structures. Considerable amount of expertise has been accumulated in the study, preservation and reproduction of paints in these historic buildings. This article describes in detail the procedures used at the Center and provides a guideline for those working in this field. The subjects discussed in the article are varied: The state of the technology; Data compilation; Logistical, budgetary and personnel considerations; Equipment for sample extraction; Where to sample; Sample identification; Mounting samples; Identification of substrates; Documentation of layer stratigraphy; Comparative analysis; Dating of paint layers; Determina tion of medium and finish types; Identification of pigments; etc.