I just thought I would share what Scotch says about the 924 tape...it is not acid free....
3M 924 ATG tape is more forgiving than the 987. It is not acid free like the 908. It is generally used in framing shops to adhere mats, as mats can be separated and rejoined more easily than with the 987. It still has a strong holding strength and is great for paper crafting.
the tape here states at the bottom it is comparable to the 3M 924, so that means it is not acid free, like it states in the ad.....thought you may want to know.
Alternative To: 3m 924, Scapa TD00, Shurtape TG236, TESA NOPI, 7002-PV9
12 ROLLS - CRAFT TAPE - ATG PHOTO TAPE - 1/4" X 36YD | eBay