Archives for category: Paper

Louis-Nicholas Robert (also known as Nicholas-Louis) was the first to make a paper-making machine, which he patented in Paris in 1799. It made a continuous roll of paper by using a paddle-wheel to scoop pulp up onto a wire mesh where it was drained and then compacted by rollers in the press section. But Robert was unable to develop the machine, and the scene of action moved from France to England, where two London stationers, Henry and Sealy Fourdrinier invested £31,830/16/4 in a vain attempt to commercialize the concept. After they went bankrupt the idea was taken up by Bryan Donkin who in 1804 built the world’s first practical paper machine at Two Waters Mill in Hertford.

The Fourdrinier’s return on their huge investment was the immortality of having the machine named after them. After development the Fourdrinier machine, which is still the workhorse of the paper industry, operates as shown in this exploded diagram.

(Both illustrations are taken from J. H. Ainsworth’s quaint Paper: The Fifth Wonder*, Thomas Printing & Publishing Co. Ltd, 1959.)

The pulp in the head box is in a solution of 97% water, and flows out through the Slice, an adjustable opening allowing thicker or thinner paper to be made. Fibers released onto the Wire will want to align themselves in the direction of the flow so the whole unit is shaken a bit from side to side so that some of the fibers end up overlapping one another thus increasing the strength of the bonds. The Wire extends from the Breast roll to the Couch roll (pronounced “cooch” in the paper world) with Table rolls and Suction boxes between them promoting drainage. When the paper leaves the Wire it is still 80% water and the Presses compact it and force out more water, getting it down to 60% or 70% water when it jumps over to the Dryers where heated felts evaporate off more water. In the Calendar stacks the paper is ironed by slippage between rollers, then wound up on the Reel and rewound to desired lengths and widths by the Winder.

Here’s a 4 minute video of Kraft paper (brown paper) being made on a huge Fourdrinier.

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

For what came before, please see  four earlier posts “Paper making by hand”, the first of which can be found here.


* For those who want to know, the other four wonders are motor vehicles, meat, steel, and petroleum. Mr Ainsworth has ranked his wonders in U.S. sales volume at 1959’s values.

Foxing — those brownish yellowy spots you often see in old books — appears mainly to occur in machine-made papers from the 19th century. Surprisingly the cause seems to be unknown. The contenders are either impurities in the pulp or size leading to fungal growth, or the presence of iron leading to what in effect would be rusting, or some problems with the bleaching process. Such testing as has been done has unfortunately found no evidence of fungi. It does show acid and iron relatively higher in relation to the rest of the sheet, but nobody seems sure whether the iron is a result of the foxing rather than the cause. The process does seem to be accelerated by humidity. Foxing doesn’t affect the integrity of the paper, and methods of “curing” the problem seem likely to damage the paper (e.g. spot bleaching), so it’s better just to accept the splodges as merely an aesthetic problem.

The fact that we don’t make papers nowadays that fox seems to suggest a manufacturing problem. The paper industry makes constant process and cleanliness improvement, and even if we don’t know what the cause of foxing is it seems to be something we are no longer up to. The Oxford English Dictionary‘s earliest reference to foxed paper is from 1848, but they do have one from the previous year referring to foxing in timber. To me that rather tilts the likelihood of causation towards an “impurities in the pulp” explanation. It seems odd that nobody has done the research though: I guess there’s no financial incentive to find out now that we don’t seem to do it any more.

Among other uses of the verb to fox are the following: to delude (as we’d use it in school, where we’d also use the same word to mean to unearth wrong-doing — it all depended on context); to have your nose turn red by excessive drinking; to turn sour in fermenting (of beer); to repair boots or shoes by renewing the upper leather; to trim a horse’s ears!


A watermark is an area of a paper sheet where the fibers are less thick allowing for a design or signature to be detected when the paper is held up to the light. In handmade paper a watermark is created by thickening up some of the wires on the mould on which the paper is formed. This is usually done by winding wire around the mesh of the mould, as you can see in the photo below.

Mould detail from Simon Barcham Greene’s website


The original purpose of a watermark seems uncertain: the circumstantial evidence suggests that they were used as a sort of trademark, an indication of which mill had made the paper. The suggestion that watermarks may have been used to identify different paper sizes and qualities, while superficially plausible, collapses under a complete lack of evidence. (See Foolscap.)

My theory of the watermark’s origin is that they started as a personal mark, identifying the individual vatman who made the sheet. After all a craftsman would in all probability provide his own tools, and how better to mark your own mould than to wind wires into it carrying your own mark? Over the centuries this watermark might easily become linked to the mill at which this craftsman ruled the roost. Of course, however plausible this suggestion may be, it too is not supported by any hard evidence.

You can see them creating the watermark on a mould at 6 minutes into this fascinating video (if you don’t see the video, click on the title of the post so you can view it in your browser). You will have to click through to YouTube to see it as Anglia Television seem to have restricted access.

The Gravell Watermark Archive at the University of Delaware provides a searchable database where the many and various watermarks used by papermakers may be consulted. Their information page does indeed provide much information.

Nowadays, commercial book papers made on Fourdinier machines can, and often do, have a watermark. Although it works in the same way by thinning out the paper to form a translucent design, the watermark is now applied after the sheet has been formed, by putting a raised design on the dandy roll, whose main function is to extract water from the sheet and to even out its formation. Papers for currency incorporate several different types of security feature including watermarks, some of a more complex chemical origin than a mere dandy roll kiss.

How many sheets of foolscap must I have disfigured in the cause of education? Nowadays, when we mostly live in that European-inspired world of boringly logical standardization based upon numbers and fractions thereof (I blame Napoléon), school children in Britain are no longer directed to write their essays on so many sides of foolscap. It’s A4 they’d use. In my schooldays foolscap meant a tall pad of white paper, around 8″ x 13″, ruled in pale blue, perhaps with a red double-lined vertical margin on the left. I suppose the word foolscap is rapidly traveling towards that fatal dictionary designation, Obsolete.

Jester’s cap watermark. National Gallery of Australia

It’s not altogether obvious why a sheet of paper slightly shorter and slightly narrower than legal size paper, should have had such a fanciful name attached to it. One theory is that paper of that size was manufactured with a watermark showing a jester’s cap (a fool’s cap), but there doesn’t seem to be evidence that sheet sizes were ever designated by watermarks. Nonetheless Keith Houston, in The Book, retells the story of the Rump Parliament’s ordering that a jester’s cap be used as a watermark on paper used by Parliament in place of the traditional royal arms. This is a neat historical joke, but does reek of back formation.

The Oxford English Dictionary will have nothing to do with it, stating in a rather lengthy aside “It has been asserted that the fool’s cap mark was introduced by Sir John Spielmann or Spilman, a German who built a paper-mill at Dartford in 1580; but we have failed to find any trustworthy authority for this statement. The Brit. Mus. copy of Rushworth’s Hist. Coll. (1659) is marked with this device. The watermark called by Sotheby ( Princ. III.) a ‘fool’s cap’, and said by him to occur in some copies of Caxton’s Golden Legend, seems not to be correctly so called. The catalogue of the Caxton Exhibition (1877) states that examples of the fool’s cap, dating from 1479, are found in a German collection there exhibited. There is no foundation for the often-repeated story that the Rump Parliament ordered a fool’s cap to be substituted for the royal arms in the watermark of the paper used for the journals of the House.”

The OED‘s earliest source for foolscap in the sense of a paper size dates from 1699, from A new dictionary of the terms ancient and modern of the canting crew, where it is defined “Fool’s-Cap, a sort of Paper so called.”

So far, so circular. The watermark idea sounds plausible, but that of course doesn’t make it true. The Oxford Companion to the Book opts, rather tepidly, for the watermark origin, adding, to complete the circularity of their argument. “it is the clearest example of a watermark being used to name a sheet size”. (Wouldn’t it actually be the only example?) The German connection hinted at above prompted me to do a bit of German research. I find no hint that they ever referred to any sort of paper in terms having anything to do with jesters’ caps.

Paper wrapper (From Paper in Printing History, Lindenmeyr Paper Corp. 1979)

For what its worth my bet is that the name — which obviously has to come from somewhere* — results from a wrapper put around sheets of paper of this sort of size and merchandised by a medieval papermaker with a jester’s cap on the label. See the wrapper in this picture: the paper it contained could easily have been called “lion”. By their very nature disposables like this very rarely survive, just as word origins for commonplace articles are infrequently recorded.

It  also seems difficult to be absolutely precise about the measurement of foolscap. I suspect that different manufacturers chopped it off at different points depending on convenience. In my size comparison with legal paper not only does the term foolscap appear to be becoming rare; legal sheets of paper seem to be at risk of disappearing. As the site informs us “Nowadays with the proliferation of cheap printers Legal paper is becoming less common as the cost of having two paper trays in a printer is significantly greater than just having one and Letter size paper is winning out when printers only have a single tray.”


* I fear that the history of British (and other) paper names is far too convoluted, extensive (and be it confessed, confusing) to be adequately covered in a blog post. The site, linked to above, makes a stab at it via the tabs in the gray bar at the top. I did have a partial go in the early days of this blog.

The first thing that struck me about Keith Houston’s The Book (W. W. Norton, 2016, $29.95) was the deconstructed binding. It’s like a three-piece binding without the sides. The only bit of cloth is the red spine. The bare binders board is exposed front and back, teaching by showing how a book’s case is constructed. I don’t think you can make it out in this photo, but the only thing on the back board which isn’t printed black on the raw board is the barcode. In order that the barcode should be scannable (i.e. have sufficient definition and clarity) they have had to print it on a white label and stick it (very straight and accurately) onto the board. It’s wonderful what these Chinese book manufacturers can (still) do.

You can see the braces down the side of the copy identifying the different elements. This technique (again, teaching by showing) continues inside the book, as can be seen from this photo of page 1.

Every Chinese schoolchild can (allegedly) tell you that Cai Lun invented paper, and Mr Houston tells the story, with narrative aplomb. Mark Kurlansky doesn’t beat about that bush “Cai Lun did not invent paper” he states in his Prologue: after his account Mr Houston also reveals to us that records exist of paper being made in China long before Cai Lun’s time, but his story is the one that sticks in the mind.

Mr Houston is a reliable and entertaining narrator. I think it’s fair to say that in his 26 pages about paper making you will develop a better understanding of the procedure than you’d garner from the entire 336-page volume Paper by Mr Kurlansky.

The focus of the book is historical. We learn about the development of writing systems, the making of papyrus, the growing popularity of parchment and paper, the work of scribes, all the major figures in book history, plus how what we now expect in a book and its format came to evolve. It’s not that you won’t develop an understanding of today’s book manufacturing industry — you’ll just pick it up as it were along the way. And the author does end the book with a very detailed colophon telling us all about this particular book’s manufacture, in China where we seem to have to go nowadays to get anything done in the old-fashioned ways at an affordable price.

The book is generously annotated. There are 62 pages of endnotes, and a sprinkling of footnotes. There isn’t a complete bibliography; rather a 3-page list of Further Reading, which is I guess OK. You can dig anything special out of the endnotes. Many color illustrations are spread throughout, printed on the cream text stock: some of these are a bit flat and murky though.

This is a very good book. I thoroughly enjoyed it and learned a lot.

Mr Houston, who is the man behind the Shady Characters blog, will be giving a talk on book history at The British Library on 3 July. I bet it’ll be worth the ten quid.


Size is a sort of waterproofing for paper. Unsized papers, like blotting paper, will just drink up ink and smudge it, so in order to get ink to sit on the sheet, various additives have been developed. These go under the name of size. The word apparently derives from the Latin “assidere” (to set next to, besiege) having come to us courtesy of early Italian papermakers who referred to it as “assisa”, slurred down to “sisa”.

The gifs below are from Paperslurry and show the effect of sizing. The paper towel on the right hand side of both pictures is designed to be absorbent, while the writing paper on the left has been sized to allow it to keep the ink on the surface.






Size coats the pulp fibers and makes them water resistant to a greater or lesser extent. It can be applied in the beater (internal or engine sizing) mixed up with the pulp along with dies, pigments and other chemicals, or it can be applied later, after the sheet has been formed, as a coating (surface or tub sizing). Size, essentially abietic acid, was made from rosin emulsified in water together with soda ash. Gum rosin is the natural pitch of the pine tree, while wood rosin is a by-product of turpentine production. For special purposes other sizes are used, animal glue, starch, casein, synthetic resins, polyvinyl alcohol, or wax emulsions.

There are four categories of sizing for papers: waterleaf — unsized, like blotting paper; slack sized — paper towels get a small amount of size to prevent them defibering while remaining water absorbent. Newsprint falls into this category too; medium sized — most printing papers to varying degrees; and hard sized — used for things like paper cups and butcher’s paper which need to be water resistant.

The U. S. Treasury used to have  department which would refurbish bills which had gotten dirty (not we hope exclusively dirty money) using a custom-built laundry machine which would soap, scrub, disinfect and iron dollar bills, saving the Treasury  from the need to print about $250,000 of new bills each year. Naturally the printers’ unions didn’t like it. Atlas Obscura tells us the story, with a small gallery of photos.

As we learned at the Crane Museum of Papermaking dollar bills (almost exclusively single dollars — we seem to be able to remember to remove larger bills from our pockets — often inadvertently go into the wash. This has the effect of washing off the potato starch with which our currency is coated, an absence which can be detected with a fluoroscope. Of course we all have one of those lying around, don’t we?

Felt is a woolen fabric made by compacting fibers together: it is non-woven. We all know what it looks like, and because this look can be imparted to woven cloth by teaseling* it, which we call felting, there has arisen a tendency to think of felt as woven. Properly speaking though it is not. The website How products are made has a full description.

I recently received a query as to what printer’s felt might be. It was a blanket, a sort of padding used to soften the impression in letterpress printing which facilitated the transfer of the ink to the paper by making the contact less smash-bang rigid. The material used might at sometime have really been felt, but was more commonly something else: paper, cardboard, anything with a bit of give in it.

We come across the word more commonly in paper-making, where a piece of felt is used as a divider between sheets of paper as they were hand delivered by the vatman. The coucher (pronounced coocher) is the one who deploys the felt, as described in Paper making by hand 2.

The felt side is that side of a sheet of paper that has not been in contact with the Fourdrinier wire, and which therefore is the smoother side of the sheet. In modern commercially-made paper this distinction is hard to see, except in the case of a laid paper.


* A teasel is a thistle-like plant of the family Dipsacus. It has hooked prickles and when the flowers are dead the plants are harvested and used in the cloth trade to raise the nap on cloth. When I was a boy woolen mills had huge frames on which hundreds of teasles were mounted. No doubt we nowadays have some man-made cheaper equivalent.

This nanoparticle-coated paper, if it ever gets to commercial viability, will necessitate the development of new printing machines. Once a book is bound — or a magazine, newspaper, catalog, brochure etc.— you can’t take it apart and return it to its original state as a single large untrimmed sheet. So printers analogous to the non-destructive scanning machines will need to be developed so that the content can be changed by leafing through the book. As the material needs to be printed by light, new presses will in any case be a necessity.

The Digital Reader has the story about reprintable paper, written by the co-inventor, Yadong Yin. The video accompanying the story shows the paper being printed, but I’m not sure it tells you much.

Basically the system “prints” the background, converting a solid blue to white in the places where the type, carried on a mask, doesn’t shut out the light. This odd YouTube video makes big claims, but does confess that the image starts to fade after five days. They do not tell us how they plan to get back the old newspapers they seem to believe will be candidates for printing again via this technology.

(If you don’t see the video because you get this post via e-mail, click on the heading to view it in your browser.)

Whether this technology will ever prove economically viable seems highly unlikely to me. Assuming (a big assumption) they can scale up the operation so that the printing side is viable, the main problem appears to be the getting back of the first printing, so that it can be updated. This can only be low-tech and killingly expensive, plus most already-read newspapers are not exactly in an ideal state for being reprinted. Or are we all going to have to have little light presses in our homes and iron our newspapers after reading them?

What we really need is a paper coating which would permit a book’s being completely erased and reprinted at one pass while remaining closed. Thus if you’d printed way too many paperback copies of Tarzan of the Apes you could, instead of throwing them out, just put them on a conveyor belt and transform them into Star Wars Episode 196. Baby steps.

I’d never really thought about it, but even back in medieval times when paper was being made by hand there were standard sheet sizes. These were no doubt less formal and rigid than today’s, but sheet sizes turn out to have grouped around certain popular sizes which played the role of standard sizes. After all you had to have moulds and deckles: these were reused time and again. If your customers got used to paper in these sizes, neighboring paper makers would tend to conform to the same or closely similar sizes.


The Schoenberg Institute for Manuscript Studies at the University of Pennsylvania has created the Needham Calculator, a tool for calculating sheet size of manuscripts. Enter a few details and bang, bang, there are the dimensions of the original sheet. The Penn Libraries blog describes the tool and its rationale.