While clearing my office the other day I noticed some plots that hadn’t really seen the light of day. I first produced it way back in 2010. Miraculously, I found the source code that generated them, so was able to make the version below. It shows results from an experminent using an inexpensive diode array spectrogarph manufacrured by Ocean Optics to measure the spectral dependence in the effecfiveness of a sunscreen at protecting our skin from UV damage.