The # 1 paper enemy is acid.
Unless your paper is made from cotton rag – which is very rare due to its high cost, most of the paper that your posters are printed on are made from wood pulp. Mechanical pulping produces paper with the shortest fiber length and does not remove lignin from the wood which promotes acid hydrolysis* and causes paper deterioration over time. You can read more about ‘The Deterioration and Preservation of Paper’ at the Library of Congress.
For short-term storage or display, the most popular poster board is made from .1875” standard corrugated cardboard (above). But more valuable posters should be stored minimally with an acid-free board. We offer a wide selection of options for preserving and protecting these valuables.
Step one: Choose the right bag.
Backer Boards and MicroChamber paper work best when stored in the appropriate poster bag. Bags when combined with a backer board protect the poster from damage during handling or from the elements when on display. You can read more on Poster bags here.
For true archival protection and indefinite storage use our Archival Armor® Mylar sleeves.
Mylar (Polyester) Sleeves
Step Two: Choose the right Backer Board
Using Acid-free backer board absorbs acid in the paper and the atmosphere. An acid-free board will eventually become ineffective and will need to be replaced. The buffered board (with 3% calcium carbonate) is superior to non-buffered. It blocks acids from entering the stored paper product. We stock four types of acid-free board.
1. The first kind is .028” thick, acid-free all the way through. Acid-free board can trap migrating acids in paper and neutralize it. Use our .028” thick board for intermediate to long-term storage. White on both sides. This board is not buffered.
2. The second type is our all white .040″ thick board. It is acid- and lignin-free and buffered with a 3% calcium carbonate buffer. This board is for indefinite storage.
Note: .028” and .040” backings although rigid, are not thick enough to keep a poster from bending. These two thicknesses should be used when posters are stored flat. Museum grade archival.
3. The next board we stock is Foam Board in .125″ or .1875″ thick. It is super rigid. This board is an indefinite-term, archival board. It has a polystyrene foam core (making it ultra-lightweight) with a laminated white, smooth facing. It is buffered with 3% calcium carbonate and is acid-free with a pH of 7.5-8.5. Museum grade archival.
4. The final board we stock is Archival Corrugated. This board is .125″ thick, B-Flute, “Banner Blue” corrugated cardboard. It is acid- and lignin-free and buffered with a 3% calcium carbonate buffer. Safe for indefinite-term storage. Museum Grade Archival.
But what if I don’t want to use Bags and Backer Boards?
Flat Files and Flat Storage boxes are also a great way to store your articles long term. If you aren’t displaying your posters for sale or handling them often, you can store them in our Archival Flat storage boxes. Used in conjunction with MicroChamber Paper these storage boxes are another way of preserving and protecting your valuables.
Store flat posters in boxes. Acid-free board or corrugated cardboard.
MicroChamber paper is a thin, pure white, exceptionally uniform 100% cotton paper, containing an unobtrusive watermark for easy identification. It is approximately one half the thickness of a sheet of bond paper. For use with all collections when paper-based or photographic items are involved. MIcro Chamber Paper contains dispersed molecular traps that remove and neutralize acids, pollutants and the harmful by-products of deterioration. It also eliminates odors such as smoke, mold, and mildew. We stock it in all standard poster sizes. MicroChamber paper is perfect for interleaving when storing your posters flat in boxes.
If that wasn’t enough, the third product we have to control the acid in your posters is deacidification spray. Although it is suggested that a conservator should do the deacidifying process, we have sold the Bookkeeper spray for years and have found it to be a non-toxic, environmentally-safe, acid-neutralizer. The magnesium oxide neutralizes the acid, leaving an alkaline reserve permanently fixed in the cellulose fibers and provides 1% buffer. It is a simple process and does not have a negative impact on the print or colors.
8 oz. pump. Covers 25 sq. ft. Nontoxic, environmentally-safe, acid-neutralizer. Works on all materials without negative impact on print or colors. The magnesium oxide neutralizes acid, leaving an alkaline reserve permanently fixed in the cellulose fibers. Provides 1% buffer.
We hope this information helps you preserve your collectibles, valuables, investments, or heirlooms. Collection protection is our specialty so if you have any questions or comments, please contact us. We’d love to hear from you.