Paper

Protective enclosures for flat paper

Loose flat paper items benefit substantially from being stored and handled in simple, protective archival enclosures.

There is a large variety of archival enclosures available commercially. They come in a range of standard sizes and include folders, envelopes and sleeves made from archival card, paper and plastics.

If you need only a small number of enclosures, you can make them cheaply and quickly from readily available materials. If you are doubtful about the archival quality of a ready-made product, you can make the enclosures yourself from archival materials you buy for the purpose.

Making a protective enclosure/folder

To make a simple folder for a single-sheet flat paper item, you will need:

• a large sheet of medium-weight archival paper, such as 160gsm archive cartridge or lightweight card;

• a cutting mat, preferably with a gridded surface;

• a sharp cutting knife;

• a metal ruler;

• a bone folder; and

• a sharp pencil and an eraser.

Click here to see diagram

To construct the folder:

• use the diagram provided to rule up and cut out the folder plan onto the paper or card. The dimensions of x—shown on the diagram—should equal the dimensions of the item to be housed plus about 3mm on each side;

• run the bone folder down the fold lines against the ruler edge, then fold the paper or card. Use the bone folder to make smooth, sharp folds;

• erase the pencil marks and construct the folder;

• determine the correct location of the slit for the closing tab and make the incision; and

• label the folder in pencil.

Some useful hints:

• use a piece of release paper—Glad Bake paper or Reemay—when bone-folding to avoid leaving a shine on the card or scratching the polyester; and

• for extra support, the base of the protective enclosure could be fitted with a piece of acid-free board.

Encapsulating flat paper

An encapsulation is a transparent envelope that is sealed around an item on all sides, leaving a small opening at each corner for ventilation. Encapsulation is widely used as an easily reversible method of protecting flat paper items for storage, display and general handling. It is a way of holding torn items together without repair. Encapsulation is most often used for archive material and maps.

An encapsulation. Photograph courtesy of the Ian Potter Art Conservation Service, University of Melbourne

The transparent material used for encapsulation is Mylar or Melinex, an inert, durable polyester film. Encapsulation involves sandwiching the paper item between two sheets of the polyester film. The paper item is held in place by the electrostatic charges between the film sheets. The margins of the film are then sealed either with acid-free double-sided tape, or by using a special polyester welding machine. The encapsulation can be sealed on all four sides, or be left open on one or two sides. Partial encapsulation is a good alternative when regular and easy access is needed.

Materials that are unsuitable for encapsulation include:

• items that crumble easily such as pastel, chalk, charcoal, pencil and gouache. The electrostatic charge on the polyester can pull the material away from the paper; and

• mouldy or insect-infested items, and some severely acidic or damaged material. The encapsulation can seal in harmful substances creating a poor microclimate.

If an item needs to be seen only from one side and is weak or acidic, a sheet of acid-free, alkaline-buffered paper or card can be enclosed behind the item. For stronger support of single-sided material, substitute the lower polyester sheet with acid-free board.

Encapsulated material can be mounted, boxed or placed in folders or drawers.

If you are planning to encapsulate a paper item, it is important to ensure that the item is suitable for encapsulation. Ask a conservator if you are unsure of the suitability of an item for encapsulation.

To encapsulate an item you will need:

• polyester film, Mylar or Melinex. The thickness of the film will depend on the size of the item to be encapsulated; 75 micron or 100 micron is generally used, and sometimes a heavier gauge for large material;

• a cutting mat, preferably with a gridded surface, or use some graph paper on top of the cutting surface;

• double-sided tape, acid-free 6mm wide—3M double-sided tape #415 is commonly used;

• a sharp cutting knife and small scissors;

• small weights;

• a metal ruler;

• an anti-static cloth or soft cloth;

• tweezers; and

• clean work surfaces and clean hands.

Click here to see diagram

To encapsulate paper:

• remove any surface dirt with a soft brush. Remove pins or staples and unfold bent corners;

• cut two pieces of polyester film at least 2cm larger than the item on all sides. For example, if the item is 300 x 210mm, cut the polyester to measure 340 x 250mm;

• place one sheet of polyester on the cutting mat and wipe away any dust. Centre the item on the polyester, lining it up using the grid on the mat. Secure the item with one or two small weights;

• carefully stick the double-sided tape to the polyester film down each side of the item, leaving a 3–5mm space between the tape and the item. Use tweezers to hold the tape and align it by using the object and the grid as a guide. Cut the tape with scissors, leaving a small space at each corner;

• remove the weight and place the second piece of polyester on top of the item, checking for dust first. Re-weight the whole package;

• lifting the top polyester sheet at one edge, peel the cover paper from one strip of tape at a time, smoothing down the polyester with your hand or a soft cloth to get rid of distortions and to ensure a good seal; and

• using the ruler and the knife, trim the edges of the encapsulation about 3mm outside the tape lines. The sharp corners of the polyester can be rounded using scissors.

Double-sided tape being applied to the edges of a polyester sheet, during encapsulation of a paper item. Photograph courtesy of the Ian Potter Art Conservation Service, University of Melbourne

Some useful hints for encapsulating paper

Keep the double-sided tape in a plastic bag when you are not using it, to avoid dust collecting on the edges of the tape. This happens very easily and the dirt is visible in the encapsulation. Bagged tape can be stored well in a domestic refrigerator.

A soft cloth or lens tissue very slightly dampened with water can be used as an anti-static cloth for cleaning the polyester.

If the item needs to be seen only from one side and is weak or acidic, a sheet of acid-free, alkaline-buffered paper or card can be enclosed behind the item. For stronger support of single-sided material, substitute the lower polyester sheet with acid-free board.

Don't wear fluffy jumpers when you are encapsulating!

To laminate or not?

Encapsulation should be differentiated from lamination. Lamination adheres the paper item to an adhesive film and a plastic layer on both sides.

Lamination is sometimes promoted as a way to preserve your paper items. But once a paper item is laminated, it is virtually impossible to remove the lamination material without damage to the item and without the use of quite strong chemicals.

Lamination serves as a protective device for cheap posters and material which can be easily replaced; but it is not reversible and definitely not recommended for valued flat paper items.

A reversible alternative is to place it in a Mylar sleeve.