Encapsulation is one of the keys to long term protection of your ephemera. See the Conservation of Ephemera page for more detail on the benefits of encapsulation.
I can encapsulate any item of ephemera up to 40" wide with any length. For standard sized items such as comics (Golden, Silver, Bronze and current), standard magazines such as Time, Playboy, etc, large magazines such as Life and Esquire, tabloids and 11x17 comic art we stock 4 mil Mylar® type D sleeves. . Mylar® is an exceptionally strong transparent film that is resistant to moisture, pollutants, oils, and acids. It contains no volatile chemicals which will migrate to the surface of the paper and cause damage. With a life expectancy of hundreds of years, Mylar® will outlast most other plastics. In addition, along with the brilliance and clarity of Mylar® which enhances the appearance of any paper collectible, it is an effective barrier against acidity which is the primary cause of paper deterioration. Each of the sleeves is sealed on three sizes. When you get your frame and insert your item, you can seal the fourth side for maximum protection.
For other sizes we make the sleeves using Archival Grade 4 mil Dupont Polyester Film Rolls. This safe, untreated film is ideal for encapsulation or used as a barrier against acid and moisture migration in framing. It has a neutral pH, contains no harmful plasticizers, and is transparent for easy viewing. Archival grade DuPont polyester (polyethylene terephthalate) has high transparency and tensile strength, non-yellowing at ambient temperatures, chemically and dimensionally stable, resistant to most chemicals, moisture and abrasion. It is approved by the Library of Congress for archival storage. We can make sleeves for any size ephemera with a maximum width of 40" with any length. For items smaller than 20" wide, we make the sleeve by folding over the Mylar®, making a sharp edge on one side. The front is cut larger than the back and flaps that can be sealed are created on three sides. For items greater than 20" wide, the sleeve is made with flaps on all 4 sides.
Both types of sleeves provide equal encapsulation protection. The images below show both products. Since the sleeves are transparent, they are difficult to see in the photos. You can click on any of the images for a larger view. Besides protection, you can see in the images below that the sleeve also provides support for the item. Both the comic and certificate are drooping before being put into their sleeve, but not after.