regarding reverting of edit by wiki guy to the best of my knowledge lightening is correct there is no such thing as digital lighting it's still lighting digital would only describe that the lighting is controlled digitally this has absolutely no effect on the actual light and thus no effect on the image if i'm not mistaken lightening would refer to processing to increase the brightness of shadows which increases the noise as both noise and the signal is boosted signal to noise ratio remains the same i'm not sure if there could be a better word than lightening though unfortunately this doesn't seem to explain where the original noise in the shadow comes from and i'm not sure if this could be consider a true noise source as it looks like its simply boosting already present noise unless if there another meaning for shadow noise