Warhol's photographic oeuvre spanned his entire career beginning in the 1960's with Photo Booth Strip portraits taken of art world luminaries, collectors and artists in Times Square. Around the late 1960's Warhol began carrying a Polaroid camera with him as 'his date' in order to document subjects. Later the Polaroid, especially the Polaroid "Big Shot," became a tool in Warhol's broader art-making practice. Polaroid portraits and still-life's were staged in The Factory, which later became source material for prints and paintings. Warhol also began using a 35 mm camera in the 1970's with which he created unique silver gelatin prints mostly printed in 8-inch by 10-inch format. In the 1980's, thanks to the suggestion of Warhol insider Christopher Makos, Warhol began to use a sewing machine to stitch the photos together creating serial images of Warhol's favorite shots. In January 1987, weeks before his death, Warhol mounted the first gallery show featuring his photographs at The Robert Miller Gallery.