A method of texturing a substrate or superstrate support material is provided, in which a thin textured film (32) is applied to the surface of the support material such as glass sheet (11). The dipping process is performed by loading a sheet (50) of the support material (11) into a frame (51) which provides a small number of small area contact points (52, 53) at which the sheet (50) is supported and lowering the frame (51) into texturing solution (59) comprising a mixture (59) of Sol-Gel (61) and texturing particles (62) comprising SiO.sub.2 monospheres. The sheet is then withdrawn from the texturing solution and the resultant film allowed to dry. The film is then sintered and the resulting film provides a textured surface suitable for the formation of a photovoltaic device.