Preservation

Comics produced before the late 1980's used paper made from the mechanical pulping process. Mechanical pulping is the process in which wood is separated  mechanically into pulp for the paper industry. Mechanical pulp was frequently bleached to increase the brightness, but retaining the lignin in the pulp. Mechanical pulp is used because it has a high fibre yield and it produces paper with high opacity and ink absorbency.
Unfortunately paper made from mechanical pulps ages badly. Acidity causes the fibres and lignin to breakdown. When the lignin  breaks down it produces yet more acidity, accelerating the process. This is the cause of the browning that can be seen on older comics. This process unless it is slowed down or halted will eventually lead to the paper becoming extremely brittle, falling apart if it is touched.

Amazing Spider-Man 42


This copy of ASM 42 shows severe signs of acidic deterioration. Printed in 1966 it is 55 years old. I purchased it in the mid 1980's and placed it in a mylar sleeve with a "acid free" backing board.

When I removed the comic from it's sleeve in 2020 I was horrified to see that the backing board had gone yellow.

Many older backing boards were merely coated with a neutral surface, under the coating the board was acidic. Over time the acid in the comic eroded the neutral coating exposing the acidic interior of the board.

Today I use backing boards that are not only coated but that are calcium carbonate buffered, and that are certified acid free.

What Can be Done ?


1. Replace old backing boards with modern calcium carbonate buffered boards.

2. Treat the comic with a non-water based de-acidification spray.

3. Place a sheet of microchamber interleaving paper (MIP) inside the front and back covers, and one in the centre of the comic.

4. Place it in a mylar sleeve

5. Store it in a dark, cool, dry environment

6. Replace the backing board and the MIP every seven years.

De-acidification


The Library of Congress has pioneered a process it calls "Mass De-Acidification" in order to preserve the many historical paper documents it archives. The process involves treating the paper with a non aqueous spray containing Magnesium Oxide. This same process can be used on a smaller scale to preserve comics.


Microchamber Interleaving Paper

Mirochamber Interleaving Paper is made from 100% cotton, and is extremely thin. The paper contains zeolites which are molecular traps which collect airborne acidic pollutant gases. These harmful gases are then neutralized by an alkaline buffer of calcium carbonate. Therefore, within the micro environment of a mylar sleeve comic aging is considerably retarded.


Storage Conditions

Q. How can copies of the same comic, printed on the same paper, at the same time show different signs of aging ?

A: Storage conditions.

Exposure to light, heat and high humidity will all speed up the acidic deterioration of comics. So comics should be stored in dark, cool and dry conditions.