This paper describes in detail an FTIR Microscope and its application to an art conservation problem. Spectral results provide qualitative identification of sub-nanogram flecks of paint and aid the conservator in assigning approximate timing of earlier repair or over-painting. The microscope accessory, equipped with a built-in high D* MCT detector, can analyze areas of a thin layer to demonstrate inhomogeneity which can provide a clue to artist techniques.