up close and personal with paper

Cocktailphysicsmoi_2 I'm here! Where's the beer? Oh, right, it's a virtual cocktail party. *waves* Hi, folks; me again, your friendly neighborhood, er, whatever. If you've been hanging around here for awhile, you've seen me before. This is my twelfth post for the Cocktail Party (unbelievable, I know) and I'm delighted to have been invited to be a regular. I'll try to live up to the—ahem—highbrow nature of the company.

Even though I'm a science geek, you've probably noticed I have a few other interests, like science fiction and poetry. One I haven't talked about much here is my love of paper, which follows naturally from my love of books. Books, for people like me, are not just media to convey knowledge or entertainment; they're objects of beauty in and of themselves. It's not just the binding that makes books artistic objects, either. The paper the text is printed on can be a sensual delight too. Fine cotton rag paper has a great texture, doesn't turn brittle the way wood pulp paper does because it's generally acid-free (the acid is why your old paperbacks are yellowing and falling apart), and holds ink beautifully as well,  especially when mechanically printed with plates or lead type (rather than, say, laser or inkjet printed). But most paper is also far stronger than you'd suspect, for a reason that might surprise you: its water content.

Remember those old Bounty paper towel commercials where Rosie the waitress stacks a full coffee cup on a wet paper towel to show how strong the paper towel is? In case you don't, here's a clip to refresh your memory (bear with it; this is from back in the day, when when we all had extended attention spans and commercials were a full minute long).

Watch Old Bounty Paper Towel at EncycloMedia.com

The standard wisdom about paper is that what makes it strong is the fibers it's made from. The tougher the fibers and, often, the longer they are, the stronger the paper. Or so conventional paper makers will tell you. Not Charles Kazilek, who calls himself the Pied Piper of Paper. (Say that fast five times!) Kazilek is a Senior Researcher at Arizona State University, where he teaches a class in scientific data presentation, including electron microscopy (more about which, later). Kazilek got interested in paper when one of his colleagues was making it out of silk fibers, a protein (as opposed to the polysaccharide cellulose), and wondered whether that still qualified as paper. (My take? Sometimes there's a fine line between cloth and paper.)

Let me digress briefly here and talk about how paper is made. Strictly speaking, you can make paper out of darn near anything that's fibrous. A while back, I made a recipe/scrapbook using papers made with various vegetables like spinach, and some embedded with chili seeds. People use cattails, bark, grass, palm fronds,  cloth rags (cotton, linen, flax), reeds (to make papyrus, a slightly different animal), sliced and dried fruits, even elephant, er, excrement, which is largely vegetal in composition. To make paper, you beat the crap out of whatever plant or other matter you've decided to use with a lot of water (this breaks down the lignin holding the fibers together), until you have a thin, gruel-like, watery soup. Chemicals and cooking will accomplish the same thing, but may add undesirable residues. Once you've got the slurry, you dip a screen into it, lift it out (wash, rinse, repeat to the desired thickness), and sponge the water through and out of it, then wait for it to dry. When it's dampish, you can peel it away from the screen and hang it up to dry completely.

Here's a little video on Korean papermaking with mulberry bark fibers:



Making Hanji from Aimee Lee on Vimeo.

Because it just settles out of the slurry, handmade paper tends to not have much of a grain while machine made paper, which is usually laid down in in a more organized way, often has a pronounced grain. This just means that the fibers line up more or less parallel rather than randomly. That's why newspaper tears more easily one way than another: tearing along the grain produces a straight tear; tear across the grain and it goes every which way. Machine-made paper may also have fillers and finishes added to it and tends to be extremely uniform in color, finish and size, like that ream of printer paper sitting on your desk, which has been bleached, and probably has a little clay in it too, to make it smooth and finish it. Handmade paper has more texture, varied thicknesses, can be made with inclusions such as petals or seeds, and can even be sculpted when wet. Depending on what it's made of, it can also be incredibly strong, which is the case with many Japanese papers, especially those made from long mulberry fibers. Mulberry or kozo paper is tough even when wet, and is often used in book repair to hold pages or spines together. It actually works far better than tape and lasts far longer.

One of the reasons even the thinnest of papers can be so strong is not just because of the tensile strength of the fibers. As Kazilek explains, "True paper, again, is not only the fibres intertwining but actually that really small microscopic amount of water where there's hydrogen bonding, and that's really key to it and that's where that strength comes in." Hydrogen bonds are among the strongest molecular bonds and one of the factors that gives the DNA molecule its relative stability. Turns out that cellulose, the primary constituent of plant matter, is hydrophilic too, which means it easily bonds to water molecules as well. So that microscope amount of water actually binds to the cellulose and to other water molecules making a microscopically gluey mass.

This was news to me. I don't tend to think of paper as having a lot of water in it. But then, I rarely think of paper on a microscopic level, either. Kazilek does. In fact, he and colleagues Gene Valentine and Jennifer Tsukayama thought about it enough to collaborate on The Paper Project, which bills itself as "a new light on paper. " That new light is one of Kazilek's specialties: electron microscopy, specifically, a scanning laser confocal  microscope.

One of my very earliest serious encounters with real world, hands-on science was at one of the first science museums on the continent in the '70s: the Ontario Science Centre (OSC) in Toronto (the Exploratorium in San Francisco was founded shortly after the same year the OSC opened in 1967 1969. Their 40th Anniversary is coming up!). If you haven't been to a good science museum, it's geek heaven. There are demos of basic scientific principles for you to not just watch, but participate in, and gadgets to "play" with while doing real science. I was particularly mesmerized by the working electron microscope, which I'd only just learned about. Hardly surprising that OSC would have one of these babies; they were first developed at the University of Toronto in 1938, by Eli Franklin Burton and students Cecil Hall, James Hillier, and Albert Prebus. In fact, OSC's was one of the early transmission models, not a scanning one, but it was still amazing to be able to see something, anything, at thousands of times its normal size. I had a low-power microscope of my own (what? Doesn't every junior science geek?) but this was, excuse the pun, another several orders of magnitude better. I don't even remember what I looked at on the screen now, but I staggered away in complete awe. There was so much there in the little teeny realm of matter! And it all looked so marvelously . . . alien.

 Transmission electron microscopes work on the same basic principle that light microscopes do. In the latter, light (photons) bounces off the object you're looking at, passes through a magnifying lens and spreads out against your cornea, making the object appear larger. Stacking various types of lenses changes how the light is bent and increases or decreases the magnification. The difference is that electron microscopes use an accelerated and focused electron beam as the illumination source rather than light. The beam passes through the prepared specimen, some of which is transparent and some of which is opaque to electrons, and scatters the beam. The scattered beam is magnified by the microscope's objective lens and recorded on a phosphor-coated screen or photographic plate to produce an image, since it can't otherwise be seen by the nekkid eye. Confocal scanning laser microscopes like Kazilek uses are one of the Cadillacs of microscopes. Or maybe the Prius. They're sort of like MRIs in that they can produce in-focus images of all the layers of thick specimens by scanning them point by point and reconstructing them via special software onto a screen or photographic plate. In this case, the laser is the light source rather than an electron beam.

Depending on the type of microscope and what the specimen is, it may need to be prepared in one way or another: mounted, stained, embedded in resin, chemically fixed, dehydrated, coated, sectioned, flash frozen, etc. Staining is one of the most common preparations of samples because various types of stains work better on different substances and differentiate them more clearly. Some stains bind better to proteins, some to starches, etc., or make parts of the specimen opaque or transparent to the beam. The upshot is that photomicrographs from the newer electron microscopes can produce some amazing colors along with those fascinating patterns.

Japanese_paper_photomicrographBut the photomicrographs taken by Kazilek don't employ any special preparation. The laser used to illuminate the samples makes the materials of the fibers themselves fluoresce in these marvelous colors. At right is a plain, undyed Sugikawa (cedar bark) & Tenjyo paper, and you can see here the lack of "grain" that characterizes handmade paper. This is what gives Japanese paper its strength, even when it's tissue-fine: there's no grain for a tear to follow, and no inherent weakness. To give you an idea of how densely woven these fibers are, this is a 100x image of an area no larger than a period. And what's in there between the fibers? Water, bonding on a molecular level to the fibers and to other water molecules. Dude, it's like the Force! It binds the galaxy, er, sheet of paper together.

I love it when two of my passions come together, but even more so when one of them is science and it leads to one of those "Science is Everywhere!" moments. In addition to the dozens of book and paper arts blogs I read, I cruise a number of science blogs and sites, and it's surprising how often those two areas collide. I found one of Kazilek's gems on National Geographic News which covered the year's ten best microscope photographs chosen by Nikon. Nikon chose another for special mention the year before, too. One of the images even appeared on the Jumbotron in Times Square. But the object of The Paper Project, Kazilek points out, is as a vehicle for science education: "This is what's so fun because what we've started to do is engage the public, in particular young scientists and young students that may not even think about doing science. We get them excited about the images, and we can decide what we want to talk about. Do we want to talk about chemistry? We could talk about hydrogen bonding. Do we want to talk about xylem and phloem? We can do that. If we want to talk about, say, photosynthesis and gas exchange you can see in their little mouths or what look like little eyes [stomata]…" Kazilek sees a strong connection between art and science, and that connection seems pretty clear in the images he produces. If you look below the surface of just about anything that's what you'll find: science.

8 thoughts on “up close and personal with paper”

  1. There’s so many process to go throw to make paper never seen it made before. I will show this to my kids when they get home. a lot of work goes into making paper.

  2. “Hi, folks; me again, your friendly neighborhood, er, whatever. If you’ve been hanging around here for awhile, you’ve seen me before.”
    Hi, nice to meet you. For those of us who haven’t been hanging around here for that long … well, not to be rude or anything, but who are you? Unfortunately, your ‘Jen-Luc’ picture has no caption with your name, and there’s no “Posted by ______” at the bottom of the post to identify you.
    From what you said, combined with hints from Jennifer about her guests, I suspect you to be Lee Kottner.
    Thanks for the info on paper; while I’d noticed the tendency of paper to tear more tidily in one direction than another and knew it had to do with the grain direction, I’d no idea that the ‘graininess’ of industrially produced paper was an artifact of the industrial process.
    Alumnus of, it turns out, James Hillier Elementary School of Brantford, Ontario, Canada.
    [To Jennifer: why not allow *style* HTML? Underlining? Bold? Quoting? Just curious.]

  3. Hi Wilson,
    Your suspicions are correct. C’est moi, Lee. We’re still working out the kinds of posting to a group blog, but eventually we’ll have the “posted by” thing licked. In the meanwhile, Jennifer’s posted a cheat sheet with our avatars on it in her “Ch-ch-changes” post, and they’ll be available with real pics and bios on our own “About” pages too. It’s sort of a piecemeal rollout.
    Hey, Brantford! You know all about the OSC then, probably. I used to trek over from Michigan to visit cousins in Hamilton.

  4. I saw a Myth Busters episode recently that you should look for. They interleaved two Yellow Pages phone books by just laying the pages against one another, page by page. They ended up with a fat book of interleaved pages with a spine at each side. They ran clamps through the two spines and tried to pull the books apart. Two mid-size cars could not do it. I apologize that I do not recall the numbers, but it took two tanks to tear apart these pages of paper that were bound together only by the hydrogen bonds that you talk about.

  5. Lee:
    Yes, I went to the OSC a few times as a kid in the 70s. At least once for a school field trip, I think! (We called it simply the “Science Centre” at the time, TLAs not being the fashion they are now)
    However, in ’89, my wife and I moved to BC, so we’re now (occasionally) taking *our* kids to Vancouver’s Science World.
    I notice that “Posted by Lee Kottner” has been added to the bottom of the original post; thanks!
    I might suggest that, given that y’ never know when y’re going to have a new reader, and because it might take us a bit to memorize which avatar goes with which writer, that someone explore the Typepad software to see if there’s a way to put the ‘Posted by…’ tag at the *beginning* of each article – even when Jennifer’s posting, especially if people are (reasonably) going to say things like, “Hi, it’s me!” Who wants to scroll down to the bottom (or try to find the ‘Ch-ch-ch-changes’ article when it’s three months old) to find out who ‘Me’ is, after all?
    Not that it’s necessary for understanding the science, of course, and some – even many – won’t care or bother. But I think a multiple-author blog ought to have the author information at the top of posts rather than the bottom. Just my opinion, though.
    Malcolm, that’s really cool.

  6. Malcolm, thanks for that heads up. I found the link here: http://dsc.discovery.com/videos/mythbusters-phone-book-friction.html but I think they’re dealing more with surface area friction than hydrogen bonds. If they’d wet the paper first, that would probably have more to do with hydrogen bonding. Still, it’s pretty cool.
    Wilson, you’re gonna have to live with our names on the avatars. One of Typepad’s quirks is that you can’t move “posted by” info to the headers. We’ll have bio pages up soon.

  7. Actually, Germany had the world’s first electron microscope in 1933. The University of Toronto had North America’s first electron microscope in 1938. It’s an absolutely gorgeous piece of equipment; it looks like a blown-glass sculpture. On display with U of T’s EM are images taken in the 1940s of paper fibres with dust particles clinging to them, and little bits of clay from pieces of paper. I thought it was a nice little coincidence to with this post’s discussion of using an EM to look at paper.

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