Samples of wool dyed with a range of nine dyes have been exposed in a Microscal fading lamp. The color changes accompanying light fading have been followed visually and instrumentally, and characterized in terms of light fastness grades, grey scale differences, color differences in CIELAB color space and in Munsell color co-ordinates. The light fastness grades are similar to those previously reported for daylight exposures. The various methods of expressing color change give detailed and quantitative measures of the effects of light on the color of natural dyes; this type of information could be of value in predicting the original color of ancient textiles.