Archives for category: Paper
The symbol for acid free paper

We rather carelessly talk about acid free paper, when what we really mean is acid neutral paper. Acid free, i.e. totally alkaline, is not an available condition in the manufacture of paper. Acidity is measured on a scale from 0 to 14. Neutrality is marked by a pH* reading of 7. Acid free paper will have a pH reading of 7 or slightly higher. In order to reduce the acidity of the wood pulp the highly acidic lignin and sulfur will have been removed in processing. and some calcium carbonate or magnesium bicarbonate may be added. Paper like this, on which lots of books are printed nowadays, is referred to as permanent paper and is covered by ANSI NISO ISO 9706 which specifies a pH level of at least 7.5. Non-permanent paper, which includes newsprint and groundwood paper, is the stuff that turns brown in sunlight, and left long enough, becomes brittle and breaks down into dust particles. It’s the acid in the paper which makes for this reaction. Permanent papers, are made from wood fiber, thoroughly treated to remove impurities. Archival papers, covered by ISO 11108, are made from cotton, cotton linters, hemp or flax, and may contain only small amounts of fully bleached chemical pulp. Archival papers are often claimed to last for 1,000 years.

Is it odd how freedom clings, erroneously, to papers? Acid free doesn’t mean free of acid, and nor does wood free mean free of wood!


* Casually used to mean acidity, but actually “potential of Hydrogen” (or power of Hydrogen”). The pH scale is used to specify the acidity or basicity of an aqueous solution. Acidic solutions (solutions with higher concentrations of hydrogen ions) have lower pH values than basic or alkaline solutions. The scale is logarithmic.

Paul Powlesland sends via Twitter these pictures of an enthusiastic attack on a paperback by some mice.

The book his mice devoured with such gusto was Robert Macfarlane’s The Old Ways. Mr Powlesland’s absence from his cabin evidently lead to a lack of crumbs being dropped on the floor, so what’s a mouse to do? Improvise. Strange, isn’t it though, that the mice seem have just torn out bits of paper, not actually consumed them? Were they looking for the good bits? It looks like the spine may have been a special target, and I guess this means the glue in the binding contained some nourishment, or maybe just tasted good.

The first picture puts me in mind of the discussion in a post of a few years ago, Is this a book? about whether individual pages or words scattered about still can be regarded as a book. If all the words are there do they really have to be in the right order to qualify? And what if some of them are in a mouse or two?

Cf. Taste in books.

Publishing Perspectives reports that the Association of University Presses has signed up to the United Nations Sustainable Development Goals Publishers Compact organized in collaboration with the International Publishers Association. In July, the IPA says, there were 100 signatories. Now at one swoop* another 150 publishers have been sort of signed up.

This is no trivial undertaking. The ten commitments you take on are:

  • Committing to the Sustainable Development Goals† (SDGs): Stating sustainability policies and targets on the signatory’s site, including adherence to this compact; incorporating SDGs and their targets as appropriate
  • Actively promoting and acquiring content that advocates for themes represented by the SDGs, such as equality, sustainability, justice, and safeguarding and strengthening the environment
  • Annually reporting on progress toward achieving SDGs, sharing data and contributing to benchmarking activities, helping to share best practices and identify gaps that still need to be addressed
  • Nominating a person [in the signatory company] who will promote SDG progress, acting as a point of contact and coordinating the SDG themes throughout the organization
  • Raising awareness and promoting the SDGs among staffers to increase awareness of SDG-related policies and goals and encouraging projects that will help achieve the SDGs by 2030
  • Raising awareness and promoting the SDGs among suppliers, to advocate for SDGs and to collaborate on areas that need innovative actions and solutions
  • Becoming an advocate to customers and stakeholders by promoting and actively communicating about the SDG agenda through marketing, sites online, promotions and projects
  • Collaborating across cities, countries, and continents with other signatories and organizations to develop, localize, and scale projects that will advance progress on the SDGs individually or through [the company’s]
  • Dedicating budget and other resources toward accelerating progress for SDG-dedicated projects and promoting SDG principles
  • Taking action on at least one SDG goal—either as an individual publisher or through your national publishing association—and sharing progress annually.

I suppose we’d expect those liberal publishers to do what they can for environmental conservation — this is especially true because the industry’s impact on the situation is pretty minor. We’re not a major source of any kind of gas — our hot air is usually locked in solid form— so the sacrifice isn’t immense. No doubt it is possible to buy paper from non-sustainable sources, but nowadays almost all books are printed on papers which are made by companies which plant more trees than they harvest, as well as containing significant amounts of recycled pulp. You’ll find the Forest Stewardship Council logo and the recycling logo on the imprints page of many books.


* I’m a bit fed up with the cliché “at one fell swoop”. Macbeth‘s Macduff has a lot to answer for, though in his usage “All my pretty chickens and their dam at one fell swoop” he does have the virtue of living consistently in the hawking metaphor. The swoop is of course the hawk’s dive onto its prey, and “fell” just means deadly. But this must now be the only context in which we find “fell” used as an adjective, though The Oxford English Dictionary does give us a rather arch example from 2011 in The New York Review of Books.

† Information about the seventeen SDGs —sustainable development goals, labelled below — may be found here.

We all know papyrus — it’s in the Bible isn’t it? It’s a sort of paper used by ancient Egyptians, isn’t it? But we are probably all a little vague about what it actually is.

Well it’s made from the pith of the papyrus plant, Cyperus papyrus. Slice it thin, soak it, then lay out a double layer of strips at right angles to each other, press the resultant web to dry it, and there you have it, a sheet you can write on.

Open Culture, via Shelf Awareness for Readers, sends us this charming video story about papyrus. It takes you through all the steps of papyrus making and goes on to give a bit of history as well as a look at current (tourist-driven) demand.

If you don’t see a video here, please click on the title of this post in order to view it in your browser.

I discover I already wrote about papyrus four years ago: Papyrus, with a different video.

It never occurred to me that you could make paper out of anything other than cellulose fibers. Wrong, wrong. CaCO3, calcium carbonate, in combination with some 20% polyethylene resins makes a very paper-like material: mix it up and roll it out. Uses no wood, no water, no bleach. And the resultant sheet is foldable and waterproof. More tuned in than me Wired was writing about stone paper in 2013.

Calcium carbonate is no stranger to the paper making process: it’s a large ingredient in the chalky coating applied to “art papers”, what we call coated papers. If you want to make a smooth paper, suitable for the reproduction of color images in fine detail, various materials, including kaolinite, calcium carbonate, bentonite, and talc are used with synthetic viscosifiers to create a sort of paint which is applied to both sides of the sheet of paper as it rolls through the machine. Doctor blades and rollers regulate the amount of coating, and the resultant sandwich of coating-paper-coating can be more or less “polished” by calender rollers. Coating can also be applied to one side of the paper only: paperback covers are often printed on C1S (coated one side) board.

But here we are talking about making paper without any wood fiber: just with calcium carbonate, which is often available as a waste product. Hunter Bliss of Pebble Printing Group in Shenzen, China, talks about this development at Printing Impressions. He tells us of stone paper manufacturing being set up in China, India and Egypt. Tireless innovator, Mr Bliss is also working on printing on reconstituted plastic bottles turned into book covering material, a project he discusses at this second video interview. Stone paper looks just like paper, though it does feel smoother than wood fiber papers do: not that this is a disadvantage! It seems to be quite widely available: Amazon sent me some booklets overnight: I figured these would be good for notes made in the open air, even in the rain.

If you don’t see a video here please click on the title of this post in order to view it in your browser.

Will stone paper invade the world of books? On the face of it there’s no reason to doubt it: we just need to get the manufacturing up to scale and there would appear to be few reasons against it. Warnings about photodegradability and lack of heat resistance may sound ominous but of course a paper book left in the sun will decay too, and excessive heat was never a book’s friend. It’s true that most of the people talking stone paper up are involved in the business, and might therefore not be entirely objective, but problems exist to be solved, and there’s an obvious attraction in the idea of using waste marble with much reduced carbon dioxide emissions.

I wonder if binding might not be a limiting factor. The little booklets I bought are 48-pagers with perforations so you can tear out pages after you’ve made a note — apparently tearing is something stone paper isn’t very good at! These 48 pages are held by two wire staples. I dare say a needle could go through to allow for Smyth sewing, but I expect perfect binding might be problematic. In a paperback book, the perfect bound pages are held together by glue which adheres to each and every leaf by the bond formed between the adhesive and the roughened up fibers of the paper. Presumably trying to roughen up the edge of stone paper would be liable to just make it smoother, not rougher, there being no fibers there to raise. Still, maybe some sort of rock-solid adhesive can do the trick, while still permitting flexibility. If Mr Bliss is right and stone paper can really be made for about half the cost of “real” paper, maybe the economics of cheaper paper plus more expensive binding will work out for the book business.

A few years back I described a waterproof paper made by Rite in the Rain. This is a regular cellulose fiber paper to which a waterproof coating has been applied.

International Paper has a piece on their renewed commitment to recycling.

This is Chapter 5 of their on-going series “Our Renewable Future”. You can access the earlier chapters in their drop down menu above the little video they have as an introduction.

Of course the paper industry has been focussed more or less seriously of recycling for all my working life, and I’ve no doubt that World Wars involved a lot of recycling, but it does at last seem that we are getting serious about the topic. It’s hard to know what motivates whom, and destroying the Amazon forest does seem to be more about clearance than lumber, but of course there are always going to be people who don’t care for anything beyond their next meal.

The phrase “going for broke” takes on a different meaning when uttered in a paper mill. Broke is the waste paper which never makes it to market — the miles of paper discarded because imperfect as the result of of a hiccough during manufacturing or messed up during the set up of the machine. After it’s gone for broke, it goes for recycling into pulp again. Once paper has had ink on it it becomes harder to recycle, so broke has ever been a valuable raw material. IP claims that the fibers can be recycled up to seven times. Each time through the process the resulting grade of paper is lower and lower: so you might start out as a handsome book, become an envelope, then a cereal box, and end up as a corrugated carton or worse the stuffing in one of those padded envelopes.

Now going for broke is pretty much what we now have to do if we are to keep the temperature of our world down to livable levels.

See also Recycling.

I was recently talking to some people who’d postponed their planned home update because the cost of the lumber needed had jumped by $40,000. The pandemic has played havoc with the wood market, and thus the paper market. If you can get two or three times more for lumber, why would you chip it up and make paper from it? As Vox tells us “For years, the price of 1,000 board feet of lumber has generally traded in the $200 to $400 range. It’s now well above $1,000.” Prices have moderated a bit recently, and will probably continue downwards as the bump in home improvement work while we were all confined to home eases off.

As if we needed any more trouble in the printing paper market, The Economist points out that demand for commercial printing has collapsed over the past 15 to 20 years, and many mills have turned their focus to packaging rather than printing papers. “Some big European wood firms, such as Metsa of Finland, have abandoned print paper (it still makes cardboard and tissues). After shutting two mills this year, Stora Enso, which is also Finnish, will derive 10% of revenue from print paper, down from 70% a decade ago.” Book paper is a pretty small subset of the printing paper industry, so pressure on book manufacturing is likely to be even harsher.

Printing Impressions tells us that the price increases in March are likely to be followed by others as almost all mills are working at near full capacity, and putting customers on allocation. It was ever thus. A paper machine is an immense beast. Deciding shut one down because of lack of demand is a huge decision — because opening it up again will take months. And constructing new capacity is an off-puttingly large investment, especially in a market which has bobbed up and down so much recently. This makes the industry’s response to changed market conditions rather slow: indeed it has often seemed in the past that the industry was able to gear up to a surge of demand just in time for the next recession to make the expansion irrelevant. “For a decade, mills have been shuttering doors one-by-one to try to control the supply-demand equation. Today, however, mill operating rates are well above 95%, have put all its customers on allocation (which prevents hoarding and is typically a function of historic usage), and have little to no flexibility in scheduling.”

Fortunately for publishers demand for books continues high, so to some extent paper price increases can be amortized over longer runs. However, we are simultaneously facing a capacity crunch in the book manufacturing sector. As always the balancing act between demand and price must continue to evolve — but don’t bet against price increases for the books you keep on buying in mass quantities.

Via Kathy Sandlers’ Technology • Innovation • Publishing comes a link to this story from New Atlas about a process for turning paper into an interactive surface.

This piece of paper has been printed in such a way that it can function as an electronic keyboard. Photo: Purdue University.

Ramses Martinez of Purdue’s School of Industrial Engineering, isn’t giving away the secret sauce when he tells us “We developed a method to render paper repellent to water, oil and dust by coating it with highly fluorinated molecules. This omniphobic coating allows us to print multiple layers of circuits onto paper without getting the ink to smear from one layer to the next one.” They claim that printing is quite cheap and can be carried our with conventional printing techniques. Perhaps we can expect early adoption in the printing of food packaging, where the technology might be used to signal freshness.

Professor Martinez reports that a sheet of paper printed by their technique can be made to function as a music player, as may be seen in this video.

If you don’t see a video here, please click on the title of this post in order to view it in your browser.

In the U.S. book business when we buy paper we talk about basis weight in referring to text stock but when we move to cover stock we talk about caliper. Caliper is the thickness of a single leaf of paper. Thus a cover measured by a micrometer at 0.010 inches is referred to as 10 point cover stock (or 10pt) — a common caliper for paperback covers. We indicate basis weight by the pound sign: #. Basis weight is always the weight in pounds of a ream of paper of a standard, basis, size. Superficially pretty straightforward.

Cover and text stocks each have both caliper and basis weight, yet we never think of the basis weight of cover stock, and I found myself last week asserting that they were in fact the same. They are not.

There are two variables in that formula for figuring basis weight: the size of a ream, and the size of the standard sheet. The ream is (almost) always 500 sheets, but there are different standard sheet sizes for different types of paper.


What is the reason for these different basic sheet sizes for different print businesses? Tradition/inertia is the simple answer. When paper was made by hand, the sheet size was determined by the dimensions of the mould used by the papermaker. For example, because sheets measuring 17″ x 22″ leant themselves to cutting into four 8 ½” x 11″ sheets, this became the standard for business stationery as the papermakers serving that business made their moulds that size. Strangely we in America have never changed our units from this quaint basis.

Why do we need to know the different basis weight calculation of cover and text stock? It comes to the fore when you venture overseas for your book production. The rest of the world tends to deal in gsm (grams per square meter, sometimes written g/m2 or g/m²) a much simpler and logical, if less picturesque, system of measurement. A book manufacturer in China may well quote you cover stock referred to in basis weight terms which they’ve converted from their gsm data. (To convert from text basis weight to gsm divide the basis weight by 0.67565. For cover stock the magic number is 0.36989. You’ll no doubt need to do a little rounding to make the answer look right.) So be aware: 100# cover stock is not the same as 100# text stock. Because the area of the basis sheet of cover stock is 1806sq.ft. while the area of the basis sheet size of text stock is 3299sq.ft., your 100# cover stock would be more like a 180# text sheet — if such a thing were available. Verso has quite a useful conversion tool.

For caliper calculation, see PPI. See also Basis weight calculation.

Thanks to Steve Morehead for this link to a Princeton post about a book from their collection, the elegantly titled Die Fabrikation des Papieres aus Stroh und vielen andern Substanzen im Grossen nach zahlreichen Versuchen beschrieben und mit 160 Mustern von verschiedenen Papiersorten bewiesen, nebst einer Beschreibung der neuesten Erfindungen in der Papierfabrikation, für Fabrikanten und alle Freunde der Fortschritte in Kultur und Industrie (Cologne: Dümont-Schauberg, 1838). Having given the title I guess I’m bound to tell non-German speakers what it means: “Making paper in bulk from straw and many other substances resulting from innumerable attempts described and demonstrated by 160 samples of various types of paper, along with a description of the newest discoveries in paper manufacturing, for manufacturers and all friends of progress in culture and industry”. The book was compiled by Louis Piette (1803-62). 

Princeton’s Firestone Library tells us “The papers are chiefly from various kinds of straw (rye, wheat, barley, oats, peas, beans, lentils, and corn), singly or in combination; some mixed with hay and/or rags; and some bleached or colored. There are also five samples of cardboard made from straw and other fibers and ten non-straw papers (hay, oakum, wood, linden bark; some with rags).”

Here’s a page showing two papers made from different materials — 83: Lime bark and rags (1 part lime bark, two parts rags) and 84: Oakum).

In 1827 Mr Piette, a native of Belgium, took over the running of the paperworks at Dillingen, in the Rhineland, which had been started by his father. He seems to have gone in for long titles — he also wrote Traité de la fabrication du papier. Contenant les procédés généralement en usage pour préparer ce produit, les diverse méthodes de collage par la disolution de gélatine et dans le cylindre ou la cuve de fabrication, le blanchiment complet des chiffons, la manière de fair les papiers de couleur, et ceux de diverse subtances, descriptions détailées des machines à fair le papier d’après les nouveaux procédés, etc. If you click on that title it’ll take you to a digitized copy at Google Books — for those of you who want to read in French a 544-page history of early paper making. The Princeton University book, Die Fabrikation des Papieres aus Stroh . . ., may also be read at Google Books, though digitized images of paper samples using different substances is a rather unrewarding format if you seriously want to compare and contrast.