What's The Difference in The Acid Free Material I Use?

Store your Digests, Paperbacks and Pulps in our POLY BAGS and protect them from dust, dirt, finger oils and other airborne pollutants. Our bags hold size and thickness tolerances and come in printed outer bags for easy product identification. We stock paperback, pulp magazine and digest bags made out of polyethylene and polypropylene. Both of these materials have passed the Photo Activity Test (P.A.T.) certifying that they are safe for long-term storage. • Polyethylene (PE) is a soft, clear material with "breathing" capabilities (lets moisture escape). It has some elasticity which allows a tighter fit than polypropylene or polyester. It has good contact clarity. • Polypropylene (PP) material is crystal-clear with excellent contact clarity. It is bi-oriented material which will not pucker or ripple over time. PP is stiffer than polyethylene. The side seals need care when inserting items, as the seams are not as strong as the PE seams. This is a short break down of the materials most often used for clear collection protection sleeves. Many people prefer mylar which is VERY clear with a "crisp" feel to it, but did you know that frequently removing a product stored in mylar CAN make microscopic tears over time? Mylar would be best used for shorter term storage. For more information and details on collection supply products, please visit

What's the difference?

This is a question people often ask concerning the poly sleeves they use for their comics, photos, vinyl records, posters, magazines and more. We stock three types of poly materials that are considered acid-free and safe for long term storage: Polyethylene, Polypropylene and Polyester. All of these materials are inert which means that there is nothing in them that can transfer to the stored item and cause damage to it. All of our poly materials have been tested by an independent lab and have passed the photo activity test which means that the material is safe for storing printed images.

The following is a synopsis that should help you to decide which material is right for you.
POLYETHYLENE: Is a bi-product of natural gas. It is a soft, clear material that has some stretch to it. It is not as clear as the other two materials listed, but does have excellent contact clarity. It comes in four different thickness. The thinner the sleeve, the higher the clarity. 3 mil is by far the most popular and generally gives the protection and clarity that is considered the standard of the industry. Our polyethylene is 100% pure virgin polyethylene.
POLYPROPYLENE: Is a very clear, high sheen, crisp material. We use bi-oriented polypropylene which mean that when the material is made, it is stretched in both directions so that over time it will not pucker (decreasing the clarity) as some polypropylenes do.
POLYESTER: Is considered the ultimate material for archival storage. It is crystal clear, semi-rigid and in acclerated tests shows no break down of the material for over one thousand years. Storing collectibles in polyester is the equivalent of using the Library of Congress archival preservation standards.
poly sleeves for collectors

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