Quantitative high-resolution electron microscopy (QHREM) involves the detailed comparison of experimental high-resolution images with image simulation based on a model and weighted by the estimated uncertainty in the experimental results. For simple metals, such as Al, models have been systematically improved using nonlinear least-squares methods to obtain simulated images that are indistinguish-able from experimental images within the experimental error. QHREM has been used to study the atomic structure of the Σ11(113)/[[horizontal bar over]110] in Al. In this paper, we focus on the method of refining electron-optical imaging parameters and atomic structure to bring the simulated HREM image into agreement with the experimental result to within the experimental error and thus yield a result more useful to the materials scientist. Uncertainties in fitted parameters are studied using the conditional probability distribution function. We discuss experimental results for atomic column locations compared with atomistic simulations of the structure of the grain boundary.