The effect of the intensity of the reference wave, a ‘zero’ component in the Fourier expansion of the object field, on the characteristics of a diffuse-object image reconstructed from a hologram without a reference beam is studied. The spatial-frequency spectrum of the reconstructed image is shown to be deformed when the coherent base intensity is lower than that of the object beam. It is shown that by taking the intensity of the reference wave higher than that of the object wave throughout the recording zone of a Gabor type hologram, it is possible to remove the nonlinear distortions of the reconstructed image, which cause deformations of the spatial-frequency spectrum.