The lenses will include composition, dyed, coated, and photochromic. Composition lenses are those that have the filtering property built into the material at the time it is manufactured. These are usually glass. Glass lenses can also be coated, usually on the back surface. Plastic lenses are usually dyed with an organic liquid to give it absorptive properties.
Photochromic lenses change density and sometimes color when exposed to UV, and visible radiation.
Name the color and estimate the absorption of each of the fixed density lenses. Draw a rough draft of the absorption curve for each lens plotting wavelength v. absorption. Based on your estimation of the absorption calculate the density of each of the fixed density lenses.