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Preservation considerations for CGC book collectors by Rune
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50 posts in this topic

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Let's focus on a few topics for pure ultra-nerd excitement:


1) Advantages of flat storage of larger paper documents (=how to position your CGC books)


2) Why an airtight environment is optimal for CGC books (=should I put my CGC books in airtight bags?)


3) Recommendations for humidity and temperature levels (=what environment is good for CGC books?)


1. Flat storage.

Regarding the flat storage of larger paper documents, (and I consider magazines and smaller comic books belonging to this category,) I found this interesting description:


"Just where exactly the belief originated that comic books are subject to less stress when stored upright and will inevitably show spine rolling if kept flat is hard to tell, but in all probability this point of view goes back to the era of pre-conservation consciousness when comic books were kept in the loose stacks mentioned at the outset. In such circumstances (for instance with large piles or comics of different sizes and weight) the fact that the spine side is thicker (accentuated by the two staples used to hold the comic book together) can create a lopsided U which will eventually roll the indivdiual comics into the same shape (hence the term "spine rolling"). There is, however, ample and informed information available which dispells the myth of the absolute imperative for vertical storage.

The Northeast Document Conservation Center (a non-profit regional conservation center in the United States, founded in 1973 and counting amongst its clients the Boston Public Library and Harvard University) advised that although vertical storage in office files or in upright flip-top archival document storage boxes is acceptable for legal-sized or smaller documents, any objects larger than 15" x 9" should be stored flat. This is due to the pull forces which documents stored in an upright position are subject to, and it is safe to assume that what is best practice for larger size documents works out well for comic books as well."

Source: http://www.panelology.info/StoringComics.html


Thus flat storage, where the forces of gravity have minimal impact on the book corners, may be a preferred storage method for CGC books (although to my knowledge no experiment has been performed to examine, how many years of storage it may take to favor flat to upright storage ;-)


2. Airtight environment.

Mylar bags may help to keep an airtight environment for our dear magazines. According to E. Gerber, one of the leading manufacturers of Mylar (ok, his potential inhability may be a small issue), it seems that airtight encapsulation is preferred:

"Isn't it bad to completely seal off the comics and make them airtight? The reality is that an airtight environment is the proper environment and by far the best one for preservation. By keeping out the oxygen, moisture and insects, and by keeping the temperature reasonably low, you can provide an environment in which your comics will become "Golden." For example, go to any library that has older volumes. Open any book and figure out why the pages are always browner at the edges and get lighter and whiter as you move towards the middle of the page. The inside of that book has not been in contact with any moisture, fresh re-circulating oxygen or light".

Source: http://www.egerber.com/aboutpreservation2.asp


But then again, this may be not big issue with CGC books. The American chemist Max Rodel investigated a few of his CGC books by testing these for water and air influx, he concluded:


"CGC's holders are both air-tight and water-tight. This is because the CGC "holder" is actually two holders, one inside the other. The outer holder that you actually touch is merely a hard protective shell. The comic book inside actually is completely sealed within an inner holder that is made from a clear, softer, flexible kind of plastic. This inner holder is independent from the hard, protective outer shell. The inner holder is sealed air- and water-tight on all four sides. So CGC'd books are completely protected from all moisture and oxygen, forever!

The CGC label is not sealed within the inner holder, but free-floats inside the outer shell. If you crack open the outer shell, the label can fall out. The outer shell is not air-tight, so one minor drawback of CGC's system is that, in the unfortunate event of flood or any water immersion, the comic book itself would be protected but the label would get wet. (CGC's competitor, PGX, has solved this potential problem by sealing the label inside the inner holder with the comic. This permanently attaches the label it to the comic book and, in my opinion, is a better system.

Perhaps you knew all this already, but I thought I would pass on things I've learned by breaking comics out of their holders to see how they were put together".

Putting CGC books in Mylar bags do make them quite pretty to look at -- and you may strengthen the holder and keep it free from scratches this way. Special Mylar bags for CGC books (including magazines) may be found at EBay.


3. Temperature, light and humidity recommendations.

Temperature and humidity levels for proper CGC book storage should be about 18 degrees Celsius and about 30 to 40% relative humidity (better safe than sorry even with the Mylar). And of course the books should not be exposed to UV light - I try to treat mine as vampires, no direct sunlight! ;-)


"The optimal temperature for books is 65° Fahrenheit (18° Celsius) with a relative humidity of 40%. This may be hard to achieve in hot Florida summers. Stability is most important. A good rule of thumb is, if you are hot and sticky, your books are, too. [...] Books are best stored in the dark, or at least out of direct sunlight."

Source: http://dlis.dos.state.fl.us/archives/preservation/books/index.cfm


Again, since the inner Barex bags seem airtight, humidity may not be much of an issue - but temperature fluctuations will be a problem. The main problem with temperature fluctuations is that this causes different materials to expand or shrink with different gradients (=material's coefficient of thermal expansion). So the ink on the cover of CGC book may expand differently than the paper it is printed on. Thus many years of temperature fluctuations cause faster deterioration:


"Extensive research and a wealth of accumulated evidence show that the lower the temperature at which it is stored, the longer paper will last. It can be demonstrated theoretically that for every 10°F decrease in temperature, the useful life of paper is approximately doubled. As a result, a number of modern research libraries and archives have been designed with storage areas in which the temperature can be maintained as low as 55°F (=13°C). Few, if any, private homes or small libraries would find such a low temperature feasible or acceptable, but the principle is sound -- the lower the storage temperature the longer the paper will endure, all other factors being equal. For most homes and libraries practical considerations dictate a temperature range of 68° to 75°F (=20° to 24°C).

Source: http://www.southalabama.edu/archives/html/guide/bookcare.htm


Furthermore, ideally books should rarely be exposed to light:


"Materials degrade more quickly when exposed to light, especially ultraviolet (UV). Surprisingly, fluorescent tubes often emit a relatively high level of UV. Lighting should be turned on only when it is needed. Ideally, storage areas should have no windows. Where windows are present, they should be covered with opaque curtains or blinds."

Source: http://www.naa.gov.au/records-management/agency/preserve/physical-preservation/artworks.aspx



See more journals by Rune

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Hi Rune,

An interesting journal entry. Thanks for taking the time to post on this subject.


Flat Storage:

Unslabbed comics (I really don't know about how slabbed comics will fair if laid flat) will develop a spine roll over time if not stored upright. I've seen this many times over my 35 years of collecting. I'n not sure of the exact cause (probably the weight of the comics on top don't help). But since it happens, I try to avoid it. I store my CGC books upright because the boxes make it conducive to do so. It would be tough getting that CGC slab off of the bottom of books that are piled 30 high. It's way easier if they are stored upright.


Airtight environment:

Does CGC claim their inner sleeve is airtight/watertight? I hadn't heard that.


Temperature, light and humidity:

I totally agree. Keep it cool, keep it dark, and keep it dry. In my opinion this is probably the most important thing you can do to extend the life of your comic books.



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Unfortunately I forgot that I had changed my forum password, so this journal entry was not attached to my forum account, hopefully Gemma can help...


The above info was collected during a few years, just hoping that these considerations could be of benefit to other collectors.


And regarding Mike's comments - yes, it is not easy using flat storage - quite a hassle getting to the bottom books, and I would be careful not to stack more than 15-20 books due to the weight impact on the bottom book that potentially could damage its holder (ok, guess you need more than 50 books to do that, but I have not tested this hypothesis). Flat storage is probably best for books you do not take out often.


I do not think that CGC has made any statement regarding the inner holder being airtight, at least I have not read any, I know some collectors think that airtight is bad for CGC books, due to an idea of harmful gasses accumulating that cannot escape - but according to Gerber access to fresh oxygen may be worse. And airtightness will limit the influences of humidity fluctuations (it should be noted that relative humidity increases as temperature decreases, so even in an airtight environment humidity can be a problem, especially with large temp fluctuations - this is also why freezing CGC books is not a good idea, as humidity will become quite high close to the freezing point and may cause condensation = book damage).

I have put my books in Mylar bags, adding an extra layer of protection - thus if they are not fully airtight, this must be very close ;-)

I remember some CGC books being submerged after flooding, only the CGC label was damaged, indicating similar results as Rodel observed, so the inner holder does seem watertight. (I never could get myself to sacrifice even an inexpensive book to test how airtight the inner holder is).





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Thanks for sharing Rune, very interesting. It's funny, I was just wondering yesterday if there was a risk of damaging the CGC books I have on display in frames on the walls of my room. From the sound of it, the preferred environment is dark, and most of my books are stored in the closet so that's covered. My best books I keep on the wall though...I'm not about to tuck them away - I view my books as pieces of art and they are meant to be displayed and enjoyed. At least I can say that my home faces North/South so that I don't have any "direct" sunlight coming in...again, still better to store them in the dark I know, but I prefer to admire them so I'll just have to keep my blinds closed more often I guess.




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Surfer...just put your slabs in frames with UV-protected glass. That way you can constantly admire them and protect them at the same time.


There are several such frames for sale on eBay.

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UV light (i.e. direct sunlight) may of course be the worst kind of light causing rapid damage to comic books, but it seems that visible light also causes damage, although it may take much longer exposure:


"What specific problems does lighting cause to collections?


The most common problems from light exposure are:


Infrared radiation heats materials, leading to their accelerated aging and embrittlement, as well as their yellowing.


Ultraviolet radiation causes materials to disintegrate or become weak, while also causing pigments or dyes to change color, and lignins in paper, as well as resins, starches, and glues to yellow or darken.


Visible light fades the colors of collections items, as well as causing darkening and yellowing of some collections items, as well as color shifts in dyes and pigments."

Source: http://www.loc.gov/preservation/care/light.html


Thus, even behind UV filters many years of exposure to visible light may not be a good thing (probably mostly a concern for very expensive books).

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My best books I keep on the wall though...I'm not about to tuck them away - I view my books as pieces of art and they are meant to be displayed and enjoyed.


I solve this by displaying my scans instead of the originals. I print the scans in 11x17 format and frame them. So they are larger than the originals and, I think, display better. And if they do get damaged by the Sun, I can just print another. UV glass does not offer 100% protection from light damage. So why chance it?



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I solve this by displaying my scans instead of the originals. I print the scans in 11x17 format and frame them. So they are larger than the originals and, I think, display better. And if they do get damaged by the Sun, I can just print another. UV glass does not offer 100% protection from light damage. So why chance it?




Never thought of such an original solution - maybe the best of both worlds, if you want to have your cake and eat it too :applause:


Or just buy two - one for the dark, one for display! :grin:

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For storing unslabbed books I really love the white mailer boxes that I bought from uline. Fairly cheap, each one will hold about 20 books in standard bags and boards. Then can be stored vertical or flat without much risk spine damage, much easier to access particular books, fits on shelves nicely and looks great if you add labels, much easier to move then the cumbersome long boxes, etc...

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Some years ago, CGC recommended reholdering books every 7th year to replace the microchamber paper, but I do not see that recommendation anymore. So I am guessing that there was some truth to the statement from this member:


"I spoke with a gentlemen that was involved in the testing and creation of conservation resources microchamber paper. I talked to him when I placed my last order with CRI. I told him what CGC said about the 7 years inert thing. He laughed, and told me that microchamber paper was designed to protect valuable ephemera collections in the most polluted environments in the US... like the library's in our biggest cities. ie: New York, Washington DC etc.....


He told me the amount of pollutants and acids they pushed thru these papers during testing was staggering, and that realistically it could be 50 years before a sheet loses its acid nuetralization qualities.... If he wanted to sell paper he could have told me somthing different, so I tend to believe him. Real nice guy, and passionate about conservation. He told me that CRI loves comic collectors, they are quirky and different from the usual conversations they have with library archivest's".





This is actually quite an interesting article, if the results are true:




Thus I am guessing that the microchamber paper will last at least a lifetime (in human years ;-) Gotta write in my testament that my grand-grand-grandchildren must replace it in 2100! :grin:

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One may of course also seek a more elaborate explanation to the deterioration of paper, explaining why it is so hard to keep the pages pure white especially in older comic books (and why many will pay a premium to avoid OW-W, O-W or worse page qualities). Although I could not find any info on the author, the following descriptions do seem to represent current knowledge:


Borrowed from:




Paper and its Deterioration


"Paper is generally made from wood pulp that is suspended in water and

matted into sheets. This can be done in one of two ways. The first way

is take logs, shred them, and form pulp. This is the cheaper of the two

ways and is thus used most often in newsprint and comic books, but it

leaves impurities in the paper. Up to one-third of the paper can be

composed of these impurities such a lignin, a complex woody acid. Lignin

breaks down in the presence of oxygen and ultraviolet light. This

light-induced oxidation of lignin is what turns newsprint yellow.


The second method has the wood fibers being prepared by digesting wood

chips in chemicals. During this process, much of the lignin and other

impurities are removed. This process is more expensive and is thus used

most often in stationary and hard cover books.


Other ways paper can deteriorate, other than light-induced oxidation

of lignin, is by oxidation of cellulose and acid hydrolysis. Oxidation

of cellulose occurs when oxygen molecules in the air attack the cellulose

fibers in the paper causing the paper to darken and increase in acidity.

Acid hydrolysis is a reaction involving heat and acids. The acids can

come from the lignin, the air itself, oxidation by-products, &c. Finally,

there is evidence that links light to the start of biological processes

that lead to brown or rust colored spots, more commonly known as foxing.


Acidity and alkalinity are measured in units of pH on a scale from 0 to 14.

A pH of 0 is the most acidic; a pH of 7 is neutral; a pH of 14 is the most

alkaline. The pH scale is based on powers of ten, thus a pH of 3.5 is 10

times more acidic than a pH of 4.5. Newsprint usually has a pH of around 4.5

when it is new while degraded paper may have a pH of 3.5. Although some

paper today is being made acid-free, the paper from which comic books are

currently being made are not."


So eventually all comic books printed on cheap newsprint paper may deteriorate, and the real challenge may be to keep the books as high as possible on this truly terrifying scale:


1. White

2. Off-White to White

3. Off-White

4. Light Tan to White

5. Light Tan to Off-White

6. Light Tan

7. Pink to White

8. Pink to Off-White

9. Pink to Light Tan

10. Pink

11. Cream to White

12. Cream to Off-White

13. Cream to Light Tan

14. Cream to Pink

15. Cream

16. Tan to White

17. Tan to Off-White

18. Tan to Light Tan

19. Tan to Pink

20. Tan to Cream

21. Tan

22. Dark Tan to White

23. Dark Tan to Off-White

24. Dark Tan to Light Tan

25. Dark Tan to Pink

26. Dark Tan to Cream

27. Dark Tan to Tan

28. Dark Tan

29. Slightly Brittle

30. Brittle


The list above should correspond to CGC's current practice when estimating deterioration of paper in comic books (source: http://www.bipcomics.com/showcase/CGCWhiteness/ ).


It may be noted that pink pages probably should not be on the list, since this page color in many cases seems to originate from the manufacturer (in female comic books) and thus is not necessarily a sign of paper deterioration.


So there may be more to the world than this crude scale, but of course the continuum from white to brittle can be separate into many arbitrary forms:



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You're welcome, thank you :) Much of the info was collected during the last years, so I thought it could be a good idea to share it all in a thread.


BTW, for more inspiration Don Rosa is known for his skills in preservation and has used a special comic book "vault" for years:


"Accumulated by world-renowned and Eisner award winning comic book artist, writer, and historian, Keno Don Rosa, this collection contained every comic book and magazine issued from every publisher from 1966 to the late 1980s. Rosa began collecting in earnest in 1962, as he purchased each comic from the newsstands, read them only once, and carefully tucked them away in optimum storage conditions, using archival boxes and a climate controlled "vault." Because they were stored in such an environment with no use of polybags, each book exhibits a brilliant sheen, deep ink reflectivity, sharp corners and a fresh newsstand appearance".

Source: http://scoop.diamondgalleries.com/Home/4/1/73/1012?articleID=54089


A tour of his "vault" is given here:



Several of his CGC books did not maintain those pure white pages (many OW-W), so I guess Mylar with acid free backing boards may be a better option than "no use of polybags"... hm

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You should consider posting this in comics general. There is a lot of misinformation in that forum that I (along with several others), have been trying to correct. Certain forum members will disagree about cutting off air flow to a comic book, but as I have said all along (and have a lot of experience in this realm as well); storing anything in an air tight environment is not detrimental as long as you control the micro environmental conditions in which they are stored in.


Other members do not understand the reholder or encapsulation process either. micro chamber paper is changed during the reholder process for a reason, and the inner well is also replaced (it is compromised during this process). Others believe the holders are air tight, but they are not, as that would require a vacuum seal. I think your post would help a lot of collectors, but unfortunately this is not the most visited area of this forum.


Thanks for posting.



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Others believe the holders are air tight, but they are not, as that would require a vacuum seal.



CGC holders are comprised of an outer-well and an inner-well. The outer-well is not air tight. The inner-well is air tight. The comics are completely sealed inside of the inner-well.



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Thank you for your comments, as you probably know the first post in this thread was just a copy of a Journal Entry at Collectors' Society (CS). So my thoughts were primarily to associate some of my key interests to my CS profile.


I will consider making a new thread in Comics General.

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Others believe the holders are air tight, but they are not, as that would require a vacuum seal.



CGC holders are comprised of an outer-well and an inner-well. The outer-well is not air tight. The inner-well is air tight. The comics are completely sealed inside of the inner-well.



It is heat sealed, not vacuum sealed. In order for it to be air tight it would have to be snug against the inner well. This is incorrect as it is not; just like third party graded coins. They are sonically sealed. If they were air tight, it would require a vacuum seal.


Quote from the CGC grading process page concerning encapsulation:



'...this is accomplished through compression and ultrasonic vibration.'


If a vacuum seal was used (which would be required to form an air tight bond) the comic book would be compromised in the process and be damaged.

Edited by mintcollector
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