Dan Flavin, Untitled, 1976. Pink, green, and blue fluorescent light, 8 ft. (244 cm) high leaning. Dan Flavin Art Institute, Bridgehampton, New York. Fluorescent tubes are no longer widely available in the diameters or colors used by Flavin. Although tubes can be custom-made and stockpiled, this technology will likely become obsolete, posing a long-term challenge for conservators of Flavin's works. Photo: Florian Holzherr. Collection of Dia Art Foundation. © 2009 Stephen Flavin/Artists Rights Society (ARS), New York