A variety of artificial and natural pigments, in addition to some natural history specimens, were exposed to a variety of light sources utilizing a variety of filters in two experiments lasting approximately three and four years. Based on this work, the author concluded the following: (1) Moderate heat has no effect on fugitive colors. (2) Moisture is essential for fading. (3) Direct sunlight is most injurious to colors, followed by diffused daylight, arc lights, filament lamps and half-watt lamps. (4) The conclusions of Russell and Abney about the destructive effect of the UV and violet end of the spectrum were confirmed, but the difference between these and other parts of the visible spectrum appear to be much less than was originally thought. (5) The original advantage of using tinted filtering glasses usually disappeared completely with a more prolonged exposure. (6) Oil colors were less fugitive than water-colors made with the same pigments, although fading still took place with long exposure to sunlight. (7) The discoloration of wood on exposure to sunlight was noted. The author recommended the avoidance of direct sunlight, the darkening of galleries after closing, and the use of electric lights instead of daylight.