I purchased PrintFile brand archival sleeves for a number of antique photos, which need to be stored for the long term. They are supposed to hold 4 prints per sleeve, but the only way to do that is to insert the prints touching back to back-- I called the company to confirm this. They assure me it's safe, but I worry about having two photographs touching back to back for long storage. Can anyone share experience or advice? Thank you in advance!