I would like to echo Mr. Thompson's advice on the storage of 4x5" negatives. Printfile storage is not all that it's cracked up to be. I've had film "stick" inside these sleeves many times over the years and ruin perfectly good negs.. These were not stored in bad locations either. Working at a museum of history makes part of my job responsible for the long term storage of film. We have found that using a polypropylene or mylar fold-loc sleeve in conjunction with an acid-free, buffered envelope, stored in metal cabinets is the way to go.