The famous Kodak High Speed Infrared Film, alias HIE, is long gone. It delivered infrared pictures with just a #25 red filter. Efke IR820, again discontinued, did give nice results with Near Infrared filters.
Today the new infrared film choice is down to Agfa Aviphot Pan 80 and Agfa Aviphot Pan 200. Both are designed as panchromatic aerial films with enhanced red sensitivity to cut through atmospheric haze. I have bought them packaged as roll film under the names Rollei Retro 80S, Rollei Infrared 400, and Rollei Superpan. There appears to be a seller of the AAP 200 film in 4x5 sheets but that seller is in the Russian Federation. Want to go there?
Infrared filters from reputable manufacturers can be seriously expensive especially in big sizes. Or they can be cheap if bought out of China via eBay. I go cheap but the principle "pays yer money and takes yer chances" definitely applies.
Three of my filters, an IR680 an two IR720, are identical performers. Using them I shoot AAP 80 at E.I.= 3 and AAP200 at E.I.= 10.
The inevitable sequence is: meter, shoot, hope.
Another IR720 filter has 1.5 stops more transmission than the others. Seller knows nothing. Only burnt one roll of film to find out.
Another infrared filter turned out to be amazingly dense. It's probably an IR950 but the seller knows nothing. Needed one blank roll to find out.
I've just discovered Ilford Delta 3200 will deliver an image with some Wood effect when exposed behind a IR720 filter. Sunny day exposure was 8 minutes at f6.7. Maybe other films can glimpse infrared as well. Experiments continue.
A non-photographic psychedelic infrared adventure:
Take a pair of close fitting motorcycle goggles and fit into each lens three or four layers of Congo Blue theatrical gel (Lee C181) and one layer of Primary Red (Rosco 27 or Lee 106). The combination blocks visible light but lets through near infrared. At first the filters seem dark but the eyes adapt quickly, the pupils dilate, and one can go around all day visually tripping out on a strange and wonderful infrared world. Warning, don't glimpse the sun. A torrent of infrared through a dilated pupil is bad.