"Scotch® ATG Adhesive Transfer Tape Acid Free 908 Gold" would be the thing to use. It transfers only the adhesive to whatever it is applied to. It has 2 layers of paper on the roll. One comes off immediately exposing the adhesive, which is on a release layer. After application that release layer is on top, you peel it off, leaving only a stripe of adhesive. There's a very nice applicator that makes application of this tape very easy. Framers often use this to adhere window mats to a backing upon which a print is mounted, or between double mats, to keep them from moving around. FWIW I've opened 25 year old mounts done by others using ATG (that was not available in acid free back then) and haven't seen any sign of bleeding or effects of acid on the mat.