I just went out on a limb and bought a roll of Polaroid Type 47. It was pretty reasonably priced, so the experiment/fun was worth it. Needless to say, I got didley squat out of it, but it was a little bit of fun at a low price point. I'm with Bryan. Go for it. If you shoot a few and get nothing for the effort, you can at least recover the glass and re-coat with AG-Plus.