Helen Frankenthaler using gas torch to heat newly applied acid patina on cast bronze ‘Gateway’ screen frame (Courtesy of Tyler Graphics, Ltd.; Photographer: Marabeth Cohen-Tyler) » Helen Frankenthaler using gas torch to heat newly applied acid patina on cast bronze ‘Gateway’ screen frame (Courtesy of Tyler Graphics, Ltd.; Photographer: Marabeth Cohen-Tyler)

Helen Frankenthaler using gas torch to heat newly applied acid patina on cast bronze 'Gateway' screen frame (Courtesy of Tyler Graphics, Ltd.; Photographer: Marabeth Cohen-Tyler)