I make POP paper all of the time for my contact sheets, the way that I do is very similar to a salt or a albumen print and doesn't have to be done in a dark room. Basically, I mix gelatin or some other collagen based product like rabbit glue or fish glue with a 10% salt water, apply it to the paper and let it dry. Afterward, I add silver nitrate mixed with water to the paper (I usually tape out 6x6 squares and only sensitize within them, so that my photographs have borders and the whole page doesn't turn black outside of the photos), let that dry and then put my negatives on top and put it out in the sun for about 6-8 minutes.
If you're interested in the chemistry here, basically the salt reacts with the silver nitrate to form silver chloride, which is light sensitive. The gelatin serves the same purpose as albumen in an albumen print and gum arabic in a gum bichromate print, to hold the components on top of the paper while keeping them from absorbing into the paper. The difference is that gelatin is a better binder and doesn't cause yellowing like albumen.