Warhol did many silk-screens on canvas; he also did acrylic on canvas. His medium was either newsprint of photography. The main point that Warhol wanted to get across was that everybody wanted to be like the famous people, that is why his art sold, the public wanted to know them and act like them. According to Warhol everybody looks alike and it is foolish that they want to be like someone else.
Warhols's technique at the beginning was the blotted line technique, which he invented and tested with for a short time on his own. The blotted line technique leads to the silk-screening technique in which Warhol is very well known for. In the silk-screening method, he picked a photograph; blew it up, transferred it in glue onto silk, and then roll ink across it so the ink goes through the silk but not through the glue. This way you get the same image, slightly different each time, which was a personal touch on Warhol's part.
Warhol made such a large quantity of Marilyn Monroe's in a row, why? He was maybe trying to get a point across. "Warhol felt tempted to see how much a consumption-oriented, snobbish art scene would accept from its undisputed star without ruining his reputation." (Lippard pg.85) Warhol was taking the artists out of the Coca Cola and Brillo Box manufacturers. He seemed to like the silk-screening because it showed sloppiness, which displayed casualness. Warhol could play around with many different colours and it would still have a good outcome because the actual picture was always the same. Warhol wanted to show the public that anyone could be an artist of his or her own.
Warhol wanted to get the point across that silk-screening was a process that the images were constructions, just as the images of stars and fame itself are intended constructions. Warhol's subjects may have been famous though he was advertising himself and his as a pedestrian. By changing the colours of his art it gives the viewer a totally different outcome of the art.