You take a fragile manuscript, or the disbound leaf of a book or newspaper, you layer it between two sheets of plastic, with some tissue included for strength and some chemicals to counteract acidity, and heat this sandwich up. Then you run it through a pair of rollers at great pressure until the plastic fuses permanently to the paper. It’s similar to what happens to new drivers’ licenses at the Department of Motor Vehicles, but instead of wallet IDs, Barrow was operating on eighteenth-century historical documents. The method became very popular; unlike traditional techniques of paper conservation, the procedure was quick and cheap and could be performed by anyone. “The Barrow laminating process,”3 wrote Clapp, “thus perfected by 1942, has withstood the test of time and has become the standard method.”
But time’s test run had not ended. No conservation lab uses lamination now; and one website for newspaper collectors advises: “Don’t laminate any item in your collection. Lamination irrevocably destroys any value!” The plastic that Barrow used was cellulose acetate, the same substance that microfilm4 of that era was made of. In 1933, around the time Recordak’s Charles Z. Case began selling microfilm to libraries, a salesman from the Celluloid Corporation pitched a new product, Protectoid,5 to the National Archives. People at the archives began laminating documents between flat plates, in a 750-ton hydraulic press. Barrow couldn’t afford the flat-plate machine and used rollers instead. (Perhaps he’d had some experience with the making of celluloid collars from his factory work.) But acetate laminations, like acetate microfilms, aren’t stable at ambient temperatures and humidities. They go brittle. The reason that Barrow knew7 so much about deacidification, in fact, is that he’d had to figure out how to counteract the paper-attacking acetic acid that was awakened in the hot plastic as it squeezed through the rollers. (His method was hotter and squeezed harder than the National Archives’s flat-plate method.) Some laminated papers turned yellow or brown; some vintages of acetate contained particular plasticizers that weakened the paper they protected; and as the Barrow Lab sold its patented lamination machines to enthusiasts around the country, and the fame of the method spread from Virginia to other state archives — and to the New York Public Library8 and the Library of Congress9—bad things began happening. “We have found10 that some materials are permanently damaged by lamination,” wrote David Stam, head of the NYPL, in 1984. Someone at a state land agency in Pennsylvania treated a great many early American manuscripts, including papers by William Penn and papers with wax seals, to a rustic version of the Barrow hot-rolled process. When the Pennsylvania State Archives inherited these documents, and saw the shape they were in, they got a grant from the Pew Charitable Trust to “disemBarrow” or delaminate them.
It was slow work. Jane Smith, a conservator, spent three years with a face mask on, using acetone and other solvents to remove the coating. “They were deteriorating rapidly, much more rapidly than anybody ever imagined,” she told me. “You could pick one up and twenty were stuck to it.” Plasticizers were “exuding from the lamination plastic,” and the result was “actually damaging the document physically, because as lamination breaks down, it lets off many nasty things — acetic acid, formic acid.” Most laminated documents aren’t this bad: “I’ve seen plenty of collections of documents that have been ‘Barrowed,’ and they’re in okay condition,” Smith said. “They’re inherently changed, because you’ve just melted plastic into the interstices of the paper, so you do not have a piece of paper anymore. You’ve introduced thermal oxidation and heavy pressure, and you’ve just filled all of the pores of the paper with melted plastic, which causes some forms of paper to become translucent. You can see through them — not completely through them like a sheet of glass, you’re not able to read them as clearly, because you’re getting conflicting information from both sides all at once.” Rumor has it that one state archive which owns a great many documents laminated by a Barrow disciple “smells like a pickle works”—the vinegar syndrome at work.
I asked Smith what the satisfactions were to her delamination work. “Anybody at all, if they were interested, could see the tremendous difference between a piece of plastic that looks like a place mat at your dinner table, for your children, and a beautiful piece of seventeenth-century British-import or early Pennsylvania paper. You went from a piece of plastic to a piece of paper, and it was phenomenal. The texture reappeared. It was really a glorious thing.” When old microfilm contorts, and the emulsioned image separates from the base, you have nothing at all left to read; when lamination buckles, on the other hand, you still have the surviving document underneath.
Swayed by the doctrine of reversibility, some paper conservators now use, in place of lamination, a much gentler technique called polyester film encapsulation, whenever they must enclose paper in plastic in order to protect it. William Minter, of Woodbury, Pennsylvania, developed this method: the document lives between two sheets of polyester that are sealed around the edges by a tiny, ultrasonically actuated titanium jackhammer that vibrates forty thousand times a second. The paper doesn’t get heated or squashed in rollers, and if for some reason you need to get your hands on the original, you can slice the margins of the encapsulation to free the paper. Less reversibly, a German company called ZFB (Zentrum für Bucherhaltung,11 or Center for Conservation) has built a room-sized machine that is able to pull apart, or “split,” a fragile newspaper or book page into two extremely thin surfaces and then glue these layers together, with a new, stronger paper sandwiched within. Barrow was “working with the best technology and the best materials available at the time,” Minter told me. “Unfortunately, it’s not working the way it was intended.”
CHAPTER 17. Double Fold
Barrow’s breathtakingly confident predictions — as to the impermanency of twentieth-century paper and as to the permanency of twentieth-century plastic — haven’t come true, but it was his misuse of the fold test that really overstimulated librarianship. In the paper-science lab, the test is almost always performed with the help of a small desktop machine called the MIT Fold Tester,1 which turns a strip of paper back and forth through 270 degrees at the rate of 175 double folds per minute. It is the most sensitive of all the physical tests for paper — sensitive in the scientific sense, meaning that test strips which are strong in every other way may seem weak when fold-tested. “Changes in folding endurance2 of paper,” write D. F. Caulfield and D. E. Gunderson of the Forest Products Research Laboratory, “show up long before there is a change in the tensile strength, bursting strength, or tearing resistance.” If you are interested in proving that a page of a book has undergone a dramatic degradation, the fold test is the test for you.
But it is an inconsistent test, according to B. L. Browning,3 a paper scientist who was a contemporary of Barrow: “The folding endurance test is less reproducible than most other physical tests, and a considerable scatter of values is commonly obtained even on relatively uniform machine-made papers.” Especially when you’re testing differences between old book papers, which can break after one, two, or five folds, the results are so variable that they must be discounted. “Values of one or only a few folds are not usually considered significant,” Browning writes. Of all tests, folding endurance is most influenced by humidity. The muggier the day, the more times your sample will be willing to fold, all other things being equal. In order to get meaningful results, you have to precondition your paper in an environment of known humidity. Barrow, self-taught, with no scientific background, only gradually became aware of these difficulties.