Mylar®
How does Mylar, which is biaxially extruded polyester film, afford more protection? The poly-bags that most everyone sells are "blown" films, affording very low density and dimensional stability. Mylar is an extruded film that is simultaneously stretched in two directions to give it maximum strength. In fact, it resists penetration by gases, such as oxygen, 300 TIMES more than the poly-bags. As for strength and stability: it is also several hundred times stronger and more stable. Keep in mind, that we are not talking about 4 or 5 times better as compared to their price; we are talking about offering the kind of protection for 100 years which poly-bags cannot offer for even one year.
Are the Mylars better to use than the cheaper poly-bags? Poly-bags are acceptable for short term storage while the comics are for sale as noted earlier. But if the storage period is longer and you do not switch to Mylar, then you qualify as DIRECTLY proportional.
Advantages of Mylar® Type D Compared to Commonly Used Plastics
- Resistance to diffusion of gases like oxygen, Carbon Dioxide, Sulfur Dioxide, etc. is 350 times greater than polyethylene.
- Permanence. There is no noticeable change in storage-100 years when compared to 2 to 5 years for others.
- Resistance to moisture, insect attack, fungus, mold, mildew, acid, oils, grease, and solvents is "excellent" compared to "fair" for others.
- Strength and creep resistance is 10 times that of polyethylene, one-third the strength of steel.
- Volatile Additions--Mylar® contains no dangerous plasticizers, slip additives, surface coatings, antioxidants, acid-hydrolysis compared to other commonly used plastics.
Acid-Free Cardboard vs. Ordinary Cardboard
If you use backing boards, use only alkaline buffered acid-free board. Be sure this specification is in writing and from someone you trust. There is no use stiffening your comics and saving a few pennies if the boards' natural acid turns your comics into "stiffs".
Acid-Free Boxes
If you do use poly-bags for storing your comics, then you should most definitely use Ac-d-Free boxes. If you already store your comics in Mylar then the Acid-Free nature of the boxes is not essential, but it is still desirable.
Mylar History
Since Mylar was first introduced about 40 years ago, the knowledge of its benefits over other common plastics was not widespread and the practice of using Mylar was even less widespread. First, the country's leading authorities on preservation, such as the National Archives and the Library of Congress, established that Mylar was, by far, the best plastic. In fact, they have made it a requirement and do not allow any deviation from their specifications.
E. Gerber introduced Mylar to the comic market in 1979. The most knowledgeable collectors have switched to Mylar since then. Slowly, museums, archival institutions and those in the collecting areas of currency and stamps have switched to Mylar. Comic collectors have been among the most knowledgeable and have been switching for years. However, we won't rest until there's a Mylar on every collectible.
Is Light Bad for our Comics?
Enough cannot be said about this topic. We would appreciate your support in teaching the collecting public that accumulated light eventually fades comic book covers. You cannot see it fade, just as you cannot see a tree grow, but go away and come back in 10 years and you will be surprised by how much that tree grew. The same thing applies to comic cover fading. Leave a comic displayed in your store and a couple of years later compare it to an identical comic stored in the dark. WOW! Unfortunately, at this point, it's too late for that comic; the damage is irreversible.
Ultra-Violet Light - UV
All plastics and glass stop some UV light, so many advertise that their "Protector" blocks UV. The truth Is that they stop only some of the damaging rays. Even Mylar will not stop all UV.
Mylar stops about 2% of UV light and is accepted as photo safe to direct contact and is used internationally by archives and museums.
What about Air and Oxygen?
Do these elements damage comics? 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.
Poly-Bags
Poly-bags will not destroy your comics. We do not preach fire and brimstone. The fact is, polypropylene and polyethylene are stable enough for the short-term storage of collectibles. They will simply afford a lot less protection against the elements. If I were a dealer or collector and wanted to keep oily fingers off my wares and valued collection, I would definitely put my "For Sale" comics into poly-bags, but only for a short term, say a couple of months.
But if I wanted them to look their best, I might try Mylar. No comic looks better than one displayed in a Mylar 4 mil Sleeve, and the extra minimal cost is worth the expense to perhaps get a better price in the sale. Taking this a little further; won't the customer believe, and rightly so, that you are treating these comics with the best care possible if you use Mylar?
On second thought, if I were a dealer or collector, I would put every comic into Mylar.
Recommendations:
In order of Most Important to Least Important:
- Keep in a cool and relatively dry place.
- Keep in the dark, or if in light, protect from UV light.
- Store in ARCHIVES (formerly SNUGS), MYLITES2 or MYLITES, with or without Acid-Free backing boards, and keep them tightly packed in a box or on the shelf.
- Store on a shelf in a closet or in a drawer, without any plastic bags.
- For more information about Mylar, paper and the science of preservation, check out this article by Bill Cole!
- Lastly, for short term protection from oily fingers, store in polypropylene bags or polyethylene bags.
The truth is, we really do care how you preserve your collectibles and are always available to answer your questions, whether or not you purchase our products or someone else's. What matters is to preserve our heritage for future generations.
Mylar trademark of DuPont Co. For the purpose of this website, Mylar shall mean any pure polyester biaxially extruded film such as Mylar D. Mellinex 455, 516 or approved equivalent.
