Altman began collecting art in 1882, when he purchased a fine pair of Chinese enamel vases that reportedly cost only thirty-five dollars (worth approximately $770 in 2010). However, according to the New York Times, by the time of his death Altman's estimated fifteen million dollar (worth approximately 340 million in 2010) art collection comprised "one of the finest private collections of paintings and porcelain in existence." Altman acquired most of his collection through the services of prominent art dealer Joseph Duveen. He made an almost weekly habit of visiting with Duveen at his art gallery on Saturday evenings after the close of business, and Altman helped Duveen relocate his business to 302 Fifth Avenue around the turn of the century