Chemical Damage

Acidity-

Though comics now use high-quality paper in the manufacturing process during the 1990s comic books were not printed on acid-free paper. Like books and other paper documents degradation of paper linked to acidity is a critical issue in persevering physical comic books.
Comics before the 1990s- before the 1990s comic books were printed on paper of inferior quality. The paper used for comics ( called newsprint) was used for its low cost and high absorbency. The manufacturing process combined with the quality of paper produced short fibers and high levels of lignin. This triggers discoloring and oxidizing ( paper turns brown) this also releases s acid that degrades the paper.

Light

Constant exposure to light will cause paper deterioration and discoloration. Light causes a chemical catalyst that led to browning. Often fading occurs on the covers of comics or any part of the comic that is exposed to light. This includes sunlight, fluorescent and metal and halogen lamps