I don't have a web page describing this technique, but it's a common trick among infrared community (as there are a couple of very good infrared dyes for this technique). A common method is to make 0.05% dye solution in 91% 2-propanol or methanol, immerse film for a predetermined period (say 2 min) and dry at once. This level of dye is sufficient for some of post-1930 infrared dyes but vastly inadequate for many dyes, so you have to select the dye very carefully. Again, I don't recommend doing it if what you want is panchromatic emulsion. Just buy it in that case.