Well, allow me to make it even more confusing: I did the exact same thing that you did with filtered and unfiltered reflections on the CD. Unfiltered, I saw the blue and green bands, and also the massive yellow sodium band and the deep red...exactly as expected. With the #19 filter in place, the yellow and red were unaffected and the blue was entirely cut out...but the green band was still dimly present. I actually managed to do a side-by-side comparison with the #19 filter halfway covering the sodium lamp, and although the green band was attenuated it was, as aforementioned, present. So, I don't know what to make of that, because there should be very, very little green coming through the #19 filter...but it was most assuredly there, and likely - in my opinion - burning the paper.
Originally Posted by Ken Nadvornick