We propose a model of the behavior of the thickness of the layers in photoresist Shipley 1350-J on a glass substrate. The photoresist is deposited using a centrifuge. The deposit is not uniform; the layers in the center are thicker than those at the rim. The model presented is obtained by fitting measurements to a modified Gaussian function with less than 1% error of the real behavior. The problem of uniformity is solved by diluting the photoresist with isopropyl alcohol. The proposed model uses parameters that control the uniformity of the photoresist layers on the substrate. This parameter control is important for obtaining high-quality optical holographic elements.