Interference microscopes use quasi-monochromatic, broad band, and white light illumination for surface topography
measurement. Fringe spacing for quasi-monochromatic illumination changes with the numerical aperture of system,
and these changes have been previously examined by others. In this article we compare changes in fringe spacing for
white light and broad band illumination for objectives with a numerical aperture of 0.13 and 0.55. We find that white
light fringe spacing changes with tilt of the object much faster than for monochromatic illumination. We also
investigate the influence of reference mirror tilt on changes in white light fringe spacing.