Hi, This may have been already reported elsewhere but as one who several years ago mentioned that reversal film processed to maximum density (not exposed but developed) could be used as a makeshift infrared passing, light blocking, filter I though I'd pass this tidbit along for those who have not thought of this other reasonably priced alternative. Assumption is that many photographers are getting rid of their colored filters since they can do adjustments in Photoshop or similar. HA! So, this means that prices of glass photographic filters must be dropping. I suppose that many "junk" piles in photo stores have such discarded filters in the $.50 bin. Glass filters are generally of much better optical quality than photographic film even if stacked! So, if you couple a blue filter with a red filter you will probably notice that the combination is pretty opaque. In fact, it may be so opaque that unless you are looking directly at the filament of a tungsten lamp you will not see through the combo. And if you perceive something it might have a deep reddish tinge. This is common to filters such as the Wratten 87. Anyway, if you'd like to make true infrared photographs but are lacking a true infrared transmitting filer try scrounging up a red #25 and a blue $47B filter or similar and stacking them photograph through the combination. It may just be what you needed. I tried this with a Fuji FinePix S9100 IR (infrared modified camera designed for quickie use in forensic applications) and the improvisation worked perfectly. BTW, I got the camera through a local student organized auction to which Fuji donated the camera. Fixed lens DSLR with live preview, etc. Neat little package! cheers, Andy Davidhazy
