The Two-Axis Diffractometer at HASYLAB was used to measure a(sin2ψ) curves
by reflecting synchrotron radiation from five different lattice planes of a cold rolled
nickel sheet. We are especially interested in the complex surface state of the
specimen and investigated the sample as delivered without further polishing and
etching. Strongly non-linear a(sin2ψ) curves were observed. Most of them vary in a
non-linear way if external uniaxial stress is applied. In this paper we study the
influence of texture using formalism based on the ODF, and evaluated for the Reuss
and the Voigt cases, respectively. Texture alone, however, is not sufficient to explain
the whole variety of the observed effects.