This publication deals with the influence upon catalytic gold particle size distribution of the washing procedures preceding calcination. The proposed preparation method and washing procedures lead to perfectly reproducible gold catalysts with a gold particle size of less than 2 nm. An explanation for the mechanism of gold particle growth is proposed. A controlled use of ammonia as a washing agent strongly improves the dispersion of gold metal on alumina. The possibility of gold complexes being stabilised by the presence of ammonia is also discussed. (c) 2005 Elsevier B.V. All rights reserved.