Photopolymers are useful for different applications such as in the development of holographic memories or holographic optical elements. Photopolymers have an undesirable feature, the toxicity of their components and their low environmental compatibility, particularly if we analyse the life cycle of the devices made with these materials and their interaction with the environment. In this sense the University of Alicante has patented new dry biocompatible photopolymer: Biophotopol. Initially this new photopolymer was optimized to holographic memories application. The main goal of the previous works was to achieve thick stable layers. On the other hand polyvinyl/acrylamide (PVA/AA) photopolymers have been widely studied by many research teams. The main drawback of an AA-based photopolymer as far as the environment is concerned is the acrylamide, a substance which has been known to be carcinogenic for many years. Recent investigations have characterized PVA/AA based photopolymers at very low spatial frequencies. In previous works we have proposed the application of interferometric techniques, both in transmission and in reflection, to characterize in real-time the modulation performance of the photopolymers. We used this approach to characterize the optical modulation properties of a PVA/AA photopolymer. With this scheme we mainly characterize the properties at very low spatial frequencies, which can be useful to analyze the applicability of holographic recording materials in another range of applications, such as recording of diffractive optical elements (DOEs). In this work we have compared Biophotopol to PVA/AA photopolymers.