Two investigations of the validity of microfading spectroscopy to predict the fading behavior of a diversity of colorants at lower light levels is discussed. The specific research question being: what is the probability that a particular sample being tested with micro-fading will alter significantly differently from the same luxhours light exposure at ambient light intensities? In one experiment two ISO Blue Wool Standards and 15 dyed papers were tested. Accelerated light aging at four illuminance levels stepping from 250 lux to one tenth of the microfading irradiance of 12.5 Mlux was conducted over different time periods using either standard fadometer lightfastness testing apparatus or a microfadometer. Samples received similar lux-hours exposure. In a second experiment a 2.2 Mlux illuminance from a microfadometer was compared to that of a QUV Weatherometer light aging chamber (with UV filtration). Ten different dyes were each faded for 10 minutes using the microfadometer and then for 21 hours using a QUV Weatherometer (with UV filtration). Samples again received the same lux-hours exposure. Results from both experiments illustrate a positive correlation between the compared light sensitivity testing methods, leading to the conclusion that fugitive colorants can be reliably highlighted by the microfading technique. In both experiments a lower value of induced color difference was observed when using microfading compared to standard lightfastness testing apparatus (light box aging) indicating that the quantative prediction of color change from real illumination in lower illuminance conditions is not secure. A short discussion of the origins of error in the technique follows.