Prior to the early 1960s, art glass would have referred to glass made for decorative use, usually by teams of factory workers, taking glass from furnaces with a thousand or more pounds of glass. This form of art glass, of which Tiffany and Steuben in the U.S.A. and Gallé in France are perhaps the best known, grew out of the factory system in which all glass objects were hand or mold blown by teams of 4 or more men. In fact, the turn of the 19th Century was the height of the old art glass movement while the factory glass blowers were being replaced by mechanical bottle blowing and continuous window glass. In the factory, every member of the team does the same job repeatedly turning out dozens or hundreds of the same item in a days work.
In an art glass studio, ideally, "production work" (goblets, vases, pitchers, etc.) shows more hand worked variation than was allowed in pure factory work environment and each piece shows some of the lead glass worker's creativity, the gaffer. In addition to smaller production pieces, most studio glass workers also try to turn out larger individual pieces which might be the equivalent of a master piece in the journeyman system of guild and factory work.