glass, i.e. high in UV content. All samples taken from early 20th century sample books for artists. (3a) Oil paints, on the vermilion darkening and carmine lake glaze on white, fading. (3b) Drawing inks on paper, all fading. The letters on the samples indicate the following exposures: 0 - unexposed; A - 0.17 Mlx h; B -- 1.7 Mlx h; C -- 6.2 Mlx h; D -- 17 Mlx h; E -- 67 Mlx h. Equivalent exposures range from A: 1 day of sunlight or 1 year at 50 lux to D: 8 months sunlight or 400 years at 50 lux. All areas are protected by a UV filter except areas marked with an asterisk (*). Note that the differences between the presence or absence of a UV filter (B vs. B*, C vs. C*, D vs. D*), while sometimes noticeable, are much less significant than differences between different exposures (A vs. B vs. C vs. D). Table 3: Sensitivity Levels and Fading Sensitivity of coloured materials to light and the number of years to cause fading. No sensitivity Low sensitivity Medium sensitivity High sensitivity Each day of exposure is assumed to be 8 hours, each year 3,000 hours. Time for a "just noticeable fade" is given as a range based on the doses for the range of ISO Blue Wools in that sensitivity category . The "almost total fade" is based on a conservative estimate of 30x the "just noticeable fade," although fading often slows down, so that an