Celluloid is made from cellulose nitrates and camphor. It was developed in America in 1867 by the Hyatt Brothers. The mixture was put into two metal moulds of the doll and steam or hot air was applied to melt the mixture so it fitted the shape of the mould. The two halves were stuck together and the doll could be painted once it had cooled. Although considered hygienic, easy and cheap to produce dolls with, celluloid is also extremely flammable and was eventually replaced with the advent of other plastics such as vinyl.