A broad band surface profiling apparatus including a reference calibrator for calibrating the apparatus to compensate for surface features of the reference surface. A user is instructed to conduct calibration measurement operations using a calibration sample having a calibration surface to obtain calibration surface topography data for the calibration sample. At each calibration measurement operation, an image representing the calibration surface topography data is displayed to the user and the user has the option to accept or reject the calibration surface topography data represented by the displayed image. The reference calibrator has a surface topography data processor and a mean surface calculator for calculating mean surface topography data using the processed calibration surface topography data accepted by the user to provide reference surface features data. A reference surface features remover is provided for adjusting surface topography data obtained for a sample surface in accordance with the reference surface features data.
