An important problem in the world of art historians is determining the type of paper on which a photograph is printed.  One way to determine the paper type is to capture a highly magnified image of the paper, then to compare this image to a database of known paper images.  Traditionally, this process is carried out by a human and is generally time-intensive.  Here we propose an automated solution to this problem, using wavelet decomposition techniques from image processing, as well as metric learning from the machine learning area.  We show, on a collection of real-world images of photographic paper, that the use of machine learning techniques produces a much better solution than image processing alone.