The PPA is an elegant and economical way to display proofs. PPA is available in either 4x5(which comes vertical/vertical) or 5x5 and includes 10 pages to hold 20 prints. Additional pages available include 4x5 vertical/vertical, 4x5 vertical/horizontal, 4x5 horizontal/horizontal, and 5x5 square. The pages can be used together to give you 4x5 and 5x5 in the same album.
