A device for quantifying the photoprotective performance of a material, the device comprising: (a) a sample supply and sample control apparatus comprising: (I) a cell having controlled optical properties, the cell capable of containing a sample comprising one or more photosensitive entities; (II) a sample temperature sensor configured to monitor the temperature of the sample within the cell; (III) a temperature control configured to maintain the cell at a specified temperature between -20°C and 100°C; (IV) a dry air supply configured to deliver low-humidity air to one or more exposed surfaces of the cell; and (V) an agitator configured to maintain sample homogeneity within the cell; (b) a light generation and light control apparatus comprising: (I) a light source, wherein the light source generates a light beam with a spectral signature between 290 and 1000 nm and an intensity between 0.01 and 5 W/cm 2 ; (II) a light beam collimating lens ; (III) an infrared filter ; (IV) a shutter ; and (V) an iris ; and (c) a test material holder positioned between the light generation and light control apparatus and the sample supply and sample control apparatus such that, when a test material is placed in the test material holder , the light beam impinges upon the test material and any penetrating light impinges upon the cell. (a) a sample supply and sample control apparatus comprising: (I) a cell having controlled optical properties, the cell capable of containing a sample comprising one or more photosensitive entities; (II) a sample temperature sensor configured to monitor the temperature of the sample within the cell; (III) a temperature control configured to maintain the cell at a specified temperature between -20°C and 100°C; (IV) a dry air supply configured to deliver low-humidity air to one or more exposed surfaces of the cell; and (V) an agitator configured to maintain sample homogeneity within the cell; (I) a cell having controlled optical properties, the cell capable of containing a sample comprising one or more photosensitive entities; (II) a sample temperature sensor configured to monitor the temperature of the sample within the cell; (III) a temperature control configured to maintain the cell at a specified temperature between -20°C and 100°C; (IV) a dry air supply configured to deliver low-humidity air to one or more exposed surfaces of the cell; and (V) an agitator configured to maintain sample homogeneity within the cell; (b) a light generation and light control apparatus comprising: (I) a light source, wherein the light source generates a light beam with a spectral signature between 290 and 1000 nm and an intensity between 0.01 and 5 W/cm 2 ; (II) a light beam collimating lens ; (III) an infrared filter ; (IV) a shutter ; and (V) an iris ; and (I) a light source, wherein the light source generates a light beam with a spectral signature between 290 and 1000 nm and an intensity between 0.01 and 5 W/cm 2 ; (II) a light beam collimating lens ; (III) an infrared filter ; (IV) a shutter ; and (V) an iris ; and (c) a test material holder positioned between the light generation and light control apparatus and the sample supply and sample control apparatus such that, when a test material is placed in the test material holder , the light beam impinges upon the test material and any penetrating light impinges upon the cell. <EOS>