We conducted a Vernier acuity experiment using orientation-modulated (OM) textures in which the overall shape (skewness) of the modulations was manipulated independently of their orientation content. Misalignments between OMs were consistent with the application of global positional tags, but not on the basis of a single cue (e.g. centroid, peak, or zero-crossing). Instead, modelling of our results in terms of orientation-opponent spatial filters not only led to an excellent fit, but also to estimates of the size and shape of these filters that correspond closely to those made by other researchers using a different task and different stimulus parameters and configurations.