An important issue in developing applications for photopolymers in holography is the effect of film thickness on recording properties. Now it is possible to create these samples with a much wider range of thickness (d = 20-1400 mum) than was previously available. We exploit these recent advances in photopolymer processing to systematically evaluate how the dynamic range of a photopolymer depends on its thickness. The results illustrate that sample performance increases linearly with thickness as predicted by standard models of volume holography. However, above a critical thickness sample performance degrades, and the angular response of recorded plane-wave holograms shows evidence of grating curvature. These distortions are likely the result of photopolymer shrinkage, which in thicker samples occurs in a nonuniform fashion. This problem limits the performance of these photopolymers and is likely to be an issue for any photopolymer that undergoes comparable polymerization shrinkage.