We present a simple computational model that works in the RGB colour space to detect moving shadow pixels in video sequences of indoor scenes, illuminated in each case by an incandescent source. A channel ratio test for shadows cast on some common indoor surfaces is proposed that can be appended to the developed scheme so as to reduce the otherwise high false detection rate. The core method, based on a Lambertian hypothesis, has been adapted to work well for near-matte surfaces by suppressing highlights. The results reported, based on an extensive data analysis conducted on some of the crucial parameters involved in the model, not only bring out the subtle details of the parameters, but also remove the ad hoc nature of the chosen thresholds to a certain extent. The method has been tested on various indoor video sequences; the results obtained indicate that it can be satisfactorily used to mark or eliminate the strong portion of the foreground shadow region.