The European project, Science and Technology for Environment Protection (STEP) aims to establish a relationship between natural and artificial aging of vegetable tanned leather and to standardize an artificial aging method. Six European partners participated in the project: the School of Conservation of Copenhagen; the CRCDG (Centre de Recherches pour la Conservation et la Restauration des Documents Graphiques) in Paris; the Leather Conservation Centre in Northampton; the Royal Library in The Hague; the Central Research Laboratory in Amsterdam; and IRPA (Institut Royal du Patrimoine Artistique) in Brussels. Reports on results of research undertaken at the CRCDG, whose mission, using high performance liquid chromatography, is to quantify N-terminal groupings that appear as a result of aging, to analyze, using gas chromatography-mass spectrometry, the products of decomposition of collagen, and to take measurements of the temperature of denaturation using differential scanning calorimetry.