Uni Pin Fineliner Pens are ultra fine markers with smooth flowing ink that features superior water resistance, so once it dries, the ink will not smear, even if water is spilt on the page. Absolutely waterproof, non-fading, lightfast and with wonderful tips with which to draw. No idea if they are archival but they are supposed to be acid free which simply means that the ink is PH neutral and should not cause your paper to deteriorate over time if you have gone to the trouble of sourcing archival papers on which to work. Being light resistant makes the Uni Pin Fineliner a great art tool as work can be displayed without fading even under continuous exposure to light. Uni Pin Fineliners are ideal for graphics and technical drawing.