Instant cameras were invented in 1947 by Edmund Land, founder of Polaroid. Such cameras use self-developing films that chemically convert to finished photographs without the intermediate step of developing a negative. Although only a handful of companies have marketed instant cameras, there are a diversity of formats, with image sizes ranging from 36 x 24mm to 20 x 24 inches. While obviously convenient, instant films' lack of negatives make reproducing photos more difficult. On the other hand, instant films unusual composition allow for innovative manipulations of the developing or finished photo, which has led to renewed interest in the format by artists and photographers.