What causes tanning and dust shadows?

[Hepcat]

What is it that causes many comic books to tan or yellow? Is it exposure to sunlight/ultraviolet light, which would also cause the colours to fade? Is it exposure to moisture/humidity? Or is heat the culprit?

 

And what about dust shadows? They're not caused by dust. Their existence would seem to imply that sunlight is the culprit.

 

 

 

 

[Mr. Zipper]

Yellowing or tanning of the pages is due to the breakdown of the paper pulp. This is caused by less than ideal storage conditions, though primarily heat. Books found in hot attics are most often tanned and/or brittle.

 

Dust shadow (darker than unaffected areas) is caused by dust settling and impregnating itself into the paper fibers over a long period of time.

 

Sun shadow (lighter than unaffected areas) is caused by light exposure.

 

You see sun shadows and dust shadows often in a strip along the edge because the book was in a stack with only a portion of an edge exposed to the dust or light source.

[Sal]

FFB, circa late 2005;

 

I spoke to Tracey Heft about this a few months ago.

 

Sun shadow/oxidation shadow: oxidation of the paper from exposure to light and air. Usually a small, darkened strip on one or more edges of the book. Might be removable or at least minimizable by washing and/or bleaching.

 

Dust shadow: usually occurs on books stored flat in piles. The dust shadow is a darkened strip where part of book was exposed to dust particles as they fell. The dust gets ingrained in the paper fibers, leaving a darkened strip. Can sometimes be dry cleaned away. Washing may set the stain and make it impossible to remove.

 

Tanning: caused by breakdowns in the cellulose chains in paper, which result in increased acidity and a darkening in newsprint and cover stock. Tends be an "all over" thing or at the very least a gradual change from tanned to untanned, with the outer edges of the folio being darker than the interior portions. Often occurs on both sides of the folio, unlike sun shadows and dust shadows, which affect only the exposed side. Usually removable by washing and/or bleaching.

 

Mr. Heft, by the way, is an expert on paper conservation

[peewee22]

Tanning can be caused by improper storage, ie, cardboard boxes (as opposed to acid free materials).

 

Some friends and I unearthed a Spidey collection in the late 80s stored in cardboard boxes since acquisition off the newsstand. Most issues from 1-10 were present. The books were perfectly preserved EXCEPT for tanning to light browning on the insides and back covers. Most had 100% gloss and ULTRA BRIGHT colors. The acids from the cardboard and excess humidity caused this effect.

[mjacobs8]

Tanning can be caused by improper storage, ie, cardboard boxes (as opposed to acid free materials).

 

Some friends and I unearthed a Spidey collection in the late 80s stored in cardboard boxes since acquisition off the newsstand. Most issues from 1-10 were present. The books were perfectly preserved EXCEPT for tanning to light browning on the insides and back covers. Most had 100% gloss and ULTRA BRIGHT colors. The acids from the cardboard and excess humidity caused this effect.

Were the books bagged and boarded?

[Hepcat]

Tanning: caused by breakdowns in the cellulose chains in paper, which result in increased acidity and a darkening in newsprint and cover stock.

 

But what would you say would be the primary cause of this breakdown - moisture, heat or sunlight?

 

 

[Mr. Zipper]

Tanning: caused by breakdowns in the cellulose chains in paper, which result in increased acidity and a darkening in newsprint and cover stock.

 

But what would you say would be the primary cause of this breakdown - moisture, heat or sunlight?

 

 

Primarily heat and and sun. As a rule of thumb, books stored in hot attics are tanned. Books stored in moist, but cool, basements can have white pages that are musty or moldy.

[Mr. Zipper]

FFB, circa late 2005;

 

I spoke to Tracey Heft about this a few months ago.

 

Sun shadow/oxidation shadow: oxidation of the paper from exposure to light and air. Usually a small, darkened strip on one or more edges of the book. Might be removable or at least minimizable by washing and/or bleaching.

 

Dust shadow: usually occurs on books stored flat in piles. The dust shadow is a darkened strip where part of book was exposed to dust particles as they fell. The dust gets ingrained in the paper fibers, leaving a darkened strip. Can sometimes be dry cleaned away. Washing may set the stain and make it impossible to remove.

 

Tanning: caused by breakdowns in the cellulose chains in paper, which result in increased acidity and a darkening in newsprint and cover stock. Tends be an "all over" thing or at the very least a gradual change from tanned to untanned, with the outer edges of the folio being darker than the interior portions. Often occurs on both sides of the folio, unlike sun shadows and dust shadows, which affect only the exposed side. Usually removable by washing and/or bleaching.

 

Mr. Heft, by the way, is an expert on paper conservation

 

Yup, that's pretty much what I wrote, but not nearly as concise.

[peewee22]

Tanning can be caused by improper storage, ie, cardboard boxes (as opposed to acid free materials).

 

Some friends and I unearthed a Spidey collection in the late 80s stored in cardboard boxes since acquisition off the newsstand. Most issues from 1-10 were present. The books were perfectly preserved EXCEPT for tanning to light browning on the insides and back covers. Most had 100% gloss and ULTRA BRIGHT colors. The acids from the cardboard and excess humidity caused this effect.

Were the books bagged and boarded?

 

Nope. Raw in the box. Soaked up puh-lenty of cardboard rays!