Nonlinear recording effects on holographic re ection gratings recorded on BB640 emulsions have been studied. Using an analytical approach to the characteristic curve of this emulsions, the density profiles recorded in the developed emulsions that correspond to the original light pattern generated by the holographic setup have been obtained. The final spatial profiles of the refraction index resulting from different exposure levels and different bleaching processes have been evaluated studying the experimental diffraction efficiency and comparing it with Kogelnik's theory. The quality of the fittings of this model with the experimental spectral responses of the final gratings has been used as a measure of the accordance between the original sinusoidal and periodical light distribution and the obtained modulation profile of the processed hologram. The range of applicability of the theoretical model to the experimental results has been evaluated using different bleaching processes.