This was a well done analysis of the types of materials used by J. M. W. Turner, taking into account details I would have never thought of. I also had no idea his painted had altered so much in the past 150years, which is a crying shame. Only two problems - 1)it was too short!! i wanted to hear more of what Townsend had discovered in her studies!! & 2) more of the photos should have been in color, it would have made some of the descriptions easier to understand.