Recent information regarding the International Standards Organization's (ISO) R105 blue-wool fading standards is reviewed, particularly the ways of instrumentally measuring their rate of fading and citations in the conservation literature of the proposed three classes of light-fastness based on ISO R105. A 1980 Japanese-American report on traveling exhibitions recommends that works that may contain colorants of the fugitive class be exhibited for no more than 5000 footcandle hours per year. The photochemically unstable character of seven traditional organic colorants confirms the practical wisdom of this recommendation to limit the total annual exposure of certain materials. A lightfastness standard newly proposed in america, a purple polyester cloth, is noted.