For archiving negatives.
Clear negative sleeves out of archive-safe, acid-free acetate. With clear negative sleeves you can make contact prints as well as archive the negatives. Pergamine Paper sleeves are of course cheaper and somewhat more archival, because their porousness allows any moisture to evaporate. However, pergamine has the disadvantage of not being see-through, so you'll have to take the negatives out to look at them or make contacts. Works for: 7x7+6x8+6x9