It was shown how the fanning noise is reduced by the dual wavelength method in the photorefractive crystals. The non destructive readout can be realized. The experiments were first done with lithium niobate doped with iron to find the optimal reading out configuration. Afterwards lithium niobate doped with iron and magnesium was used to record the high signal to noise ratio holograms. In order to retrieve the hologram with filed losses a cylindrical lens was added into the reference path.