Two dimensional photonic crystals slabs can be recorded using a double exposure of a photoresist film to an interference fringe pattern. In order to present an expressive PBG (photonic band gap) for a desired region of the electromagnetic spectrum, the geometry of the 2 dimensional structures must be appropriately defined. Besides the geometric requirements, the material itself, in which the structures are recorded, must be transparent and present high refractive index in electromagnetic region of the PBG. In this paper we design and fabricate two dimensional PC (Photonic Crystals) in dielectric films on glass substrates. The use of optical materials instead of semiconductors allows the development of processes able to produce P. C. for the visible part of the spectrum.