Backing board

A backing board (or backer board) is a comic book- or magazine-sized piece of cardboard designed to keep comic books flat during shipment or storage. Backing boards became popular during the comics boom of the 1990s, when more collectors became interested in the storage and preservation of their comic books with the goal of future financial gain.

Comic book collectors refer to a comic book that has been placed in a polypropylene (or better polyethylene/Mylar) bag with a backing board as "bagged and boarded."

Varieties

While uniformly white, backing boards come in a variety of materials and sizes.

Grades

As of 2006, there are three grades backing boards:

1. Chipboard - A pH-neutral backing board that is 30 point thick. Chipboard contains acid and is recommended for short-term storage. These are white on one side and bare cardboard on the other.
2. Acid-free - Acid-free boards trap and neutralize acids in paper that would otherwise permeate and slowly destroy them. These boards are usually 28 point thick and white on both sides, one shiny, one matte. Acid-free backing boards are recommended for long-term storage.
3. "Super" acid-free - For archival-quality protection, these acid-free backing boards are buffered with calcium carbonate, which prevents the board from breaking down, supposedly. These boards are the thickest, at 40 points.

Sizes

In addition to the magazine and recently introduced manga sizes, backing boards for American comic books are sized based on the era of publication, including current, "regular", Silver Age, and Golden Age sizes.

Common sizes of comic book backing boards

Format	Average Size	Bag size
Current	6-11/16 in. by 10⅜ in.	6⅞ in. by 10½ in.
Regular	6-15/16 in. by 10⅜ in.	7¼ in. by 10½ in.
Silver Age	7-3/16 in. by 10⅜ in.	7⅛ in. by 10½ in.
Golden Age	7-11/16 in. by 10⅜ in.	7¾ in. by 10½ in.
Magazine	8-11/16 in. by 10¾	8¾ in. by 11 in.
Treasury edition	10⅛ in. by 14-1/4 in.	10⅜ in. by 14½ in.