Comic bags and boards explained: sizes, materials and what to buy
Published Sep 14, 2026 · Updated Sep 14, 2026 · 1 min read
Short answerA bag protects a comic from dirt and handling; a board keeps it flat and, if it is acid-free and buffered, absorbs acid. Bags come in Golden, Silver, Current (Modern) and magazine sizes to match how comic dimensions have shrunk over the decades, and in three materials: polypropylene and polyethylene (cheap, replace every few years) and Mylar (polyester, archival, lasts decades). Buy the size that matches the book's era and use boards labelled acid-free.
Sizes
Comics got smaller over time, so bags and boards come in era sizes. Approximate widths:
| Size | Fits | Typical bag width |
|---|---|---|
| Golden Age | 1938 to mid-1950s | about 7¾ in (19.7 cm) |
| Silver Age | mid-1950s to about 1980 | about 7⅛ in (18.1 cm) |
| Current / Modern | 1980s to today | about 6⅞ in (17.5 cm) |
| Magazine | Oversized magazines and treasuries | wider formats |
The sizes overlap; a Silver Age bag fits most Bronze Age books comfortably, and many collectors use Silver size for everything from the 1960s to the 1980s. If a book is a tight fit, go up a size — forcing a comic into a bag causes spine stress.
Materials
- Polypropylene (PP) — clear, cheap, the standard shop bag. Yellows and becomes brittle after some years; replace periodically.
- Polyethylene (PE) — softer and cloudier, cheap, similar lifespan.
- Mylar (polyester, often sold as Mylites) — crystal clear, inert, archival; lasts decades and does not off-gas. The right choice for keys and long-term storage; costs more.
Boards
A backing board should be acid-free, and ideally buffered with calcium carbonate to neutralise acid migrating from the paper. Boards are sold in the same era sizes as bags. Put the board behind the book, glossy side towards the comic, and slide the pair into the bag with the opening at the top.
Tape
Seal the bag flap with a small piece of tape onto the bag, not the board, and never onto the comic. When opening, cut the tape rather than peeling, which can pull the flap into the book.
Slab bags
Graded slabs go in their own oversized bags to prevent scuffs on the case.
See How to store and preserve comics for the rest of the storage picture.
Written by the Rare Comics Collectors grading team. Spotted an error or have a question this guide does not answer? Tell us.