Stencil Paper

Patents for mimeograph stencils frequently describe the paper used and the qualities that made it ideal for the duplicating process: it had to be strong enough to handle repetitive stresses, have fibers that allowed an even coating of an ink-proof material to be applied, and tolerate precise perforations or disruptions in that coating for the ink to seep through only in a specified area and at a rate conducive to ongoing printmaking.

“I then take sheets of an open lace like material, such as Japanese Yoshino paper, for example….”

“This invention relates generally to type impressible stencil sheets suitable for use on the mimeograph… in which is employed an open porous base, such as yoshino, provided with a normally impervious coating….”

In carrying out the invention, I employ a base of open, porous material, such as the bibulous* Japanese paper commonly known as “yoshino.”

My invention relates to stencil-sheets of the type commonly used for autographic and typewriting duplication and particularly to stencil-sheets consisting of a fibrous and porous base (such as Japanese paper)….

Beginning with David Gestetner’s 1885 patent that utilized Japanese paper made from bamboo or gampi (Diplomorpha sikokiana, a shrub endemic to mountainous regions of Japan that is resistant to cultivation), mimeograph stencil-sheet patents frequently mention using Japanese paper as a base. Gampi is less frequently used because of its relative scarcity, while another plant intimately tied to Japanese papermaking, mitsumata (Edgeworthia chrysantha, also alternative spelling mitzumata) saw its use limited to banknote-paper and, nowadays, to document conservation. Still, gampi’s and mitsumata’s use is of interest and so some details are provided below.

Kozo (Broussonetia papyrifera or, in some resources B. kazinoki Siebold) will be the focus of discussion here, though the others have some relevance. for example, Gampi, mitsumata, and kozo are mentioned in patents filed by the Ricoh Corporation for the creation of heat-sensitive stencils used in the electronic stencil duplicating processes of Ricoh and quite possibly Risograph machines, though the latter, along with tattoo-stencil paper might be synthetic. As stencils coated in thermoplastic resin are not the focus of this post, I will not consider them beyond this brief mention. The patents are available here, here, and here (may be duplicates presented in different countries).Back to the plant-fiber papers of relevance here.

Below are some documents that introduce them in a basic way and in the context of papermaking. [Note that the first document attached below has two misspellings: Diplomorphs should be Diplomorpha, and Wikstreomia should be Wikstroemia. All three documents from this set included here were not well edited and contain typos and wording errors. I still leave them here in case they are of use in any way.]

W. B. Proudfoot (1972, 57) reports that Gestetner learned of Japanese paper some years prior to the date of his patent application when he was employed selling Japanese kites that were made with traditional paper, and indicates what made these papers suitable for Gestetner’s forays into stencil-making:

Its special characteristics as a stencil base were the long, fine but strong fibres forming a sheet of relatively open texture. It was thus that the teeth of the wheel pen after piercing the wax could easily perforate this special tissue without breaking any of the fibres. (57)

Paper made from kozo fibers is by far the most common type of what the patents frequently referred to as “Japanese paper.”

Now known by the general term washi, the types of kozo, gampi, and mitsumata-fiber papers that are of concern to mimeograph enthusiasts were traditionally products of cottage industries by which craftsmen developed much sought-after and extremely versatile products. A perfectly acceptable series of Wikipedia entries provide information on the types of products for which paper-mulberry-derived washi is traditionally manufactured and well-suited. More is available under the term “Japanese tissue,” and this page lists the more than eighty varieties or classifications of washi paper as found in Japan today.

Meanwhile, it is the “cottage industry” detail that will be supremely important in years to come.

From here on out, I’ll be talking about and featuring the production of solely kozo paper for two reasons. First, it’s the only fiber that was ultimately widely used in the production of mimeograph stencils; second, kozo is found growing “feral” in parts of the world it’s not endemic to and is a prolific self-propagator (clonally and by seed), making it a prime candidate for local community use in many parts of the world.

Broussonetia papyrifera, commonly known as paper mulberry, is native to Asia. The website (Flora of China) lists its range as the following Chinese provinces and other countries. China: Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, SE Xizang (Tibet Autonomous Prefecture), Yunnan, and Zhejiang. Other countries: Cambodia, Japan, Korea, Laos, Malaysia, Myanmar, Sikkim, Taiwan, Thailand, Vietnam; various Pacific Islands. A history of the plant’s introduction to Europe and subsequent taxonomic debates/decisions can be found here. The full text is unavailable, but perhaps it explains why the plant is no longer considered a true mulberry (genus Morus). Other scholars have studied the plant’s translocation out of Asia to greater Oceania where it found use in the making of tapa cloth (see bottom of article for more information).

Paper mulberry (kozo) in the US

According to many, many sources, paper mulberry is quite invasive – it favors disturbed soil and is capable of reproducing quickly. While early plants that were brought over to the US for horticultural uses were all male, eventually female plants made it here, with concomitant issues: the pollen is incredibly allergenic (Islamabad, Pakistan seems to consider it an allergenic scourge), and the results of sexual reproduction are easily spread even more widely than the clonally-reproduced versions.

If you don’t live in the US and are thinking of bringing paper mulberry to your region, it’s highly suggested that you only use rooted cuttings from male plants to avoid the “problem” being faced in some parts of the southeastern United States. I put “problem” in quotes because 1) I’m not a plant-purist, but most importantly, 2) this is an opportunity masquerading as a problem though I urge folks to not be cause a problem while searching for opportunity.

A quick look at the maps below will reveal to you the distinct opportunity presented by the free-for-the-harvesting papermaking-cornucopia that now exists in the US. Each of these shows some version of the supposed distribution of paper mulberry (see later in this post for information on another washi raw-material, tororo aoi or sunset muskmallow). With careful attention, paper mulberry can be found and cultivated by coppicing to allow for the more favorably-sized shoots to take precedence.

The process of using paper mulberry to make washi

The making of paper-mulberry paper (an awkwardly worded phrase if ever there was one, so henceforth to be referred to as simply washi paper) was developed in China and reached a high degree of sophistication there, as well as in Korea and Japan. While most of the video sources provided here have a focus on the Japanese tradition, Korean papermaking techniques and products, though less widely known, are of value.

Aimee Lee offers this beautiful write-up of the work of Jang Seong Woo, featured in the video above, who continues the traditional art of Korean papermaking. She details the process’s basic steps in a video here, and several more videos are linked from her website.

Making washi

What follows is a series of videos that explain or explore the washi-making process. A written extrapolation will be provided below all the embedded videos in this section.

The first video is a brief walk through the Japanese process that provides no explanation but that will give you an understanding of what’s entailed.

This next video provides a few more details about a specific company’s process for making extremely thin paper that is used by artifact conservators worldwide.

For an embedded video that shows the Hidakawashi company’s process in more detail (including the automated portions), see their site here. Also, see their facebook page for updated videos and information.

The most extensive and detailed video in this post shows the majority of the steps required, all undertaken in the traditional way.

Here we are shown the steps:

  1. Harvest kozo when stalks are about the thickness of one’s forefinger in December/January, when the plant is dormant and all the leaves have been shed. Wikipedia asserts (without citation) that washi-making “is often undertaken in the cold weather of winter, as pure, cold running water is essential to the production of washi. Cold inhibits bacteria, preventing the decomposition of the fibres. Cold also makes the fibres contract, producing a crisp feel to the paper. It is traditionally the winter work of farmers, a task that supplemented a farmer’s income.”
    As you can see, these plants are coppiced, meaning that they are completely pruned every year so that no dominant leader overshadows the rest. Cut to the ground (or rather, leave a “knob” of the parent plant just above ground level), the plants are long-lived and able to regenerate each spring. Cutting the stalks when they are this size and not much thicker results in fibers of higher quality and cutting on the diagonal makes peeling easier.
  2. Trim the switches to fit the inner dimensions of the steamer (1 meter/ 1 yard). This allows for even stacking and easy peeling.
  3. Steam the switches. Some sources suggest they should be steamed for 30 minutes, and others say 3 hours. Steaming facilitates peeling, however Chinese traditional-lifeways YouTuber Li Ziqi’s method has her peeling the bark (from significantly more mature saplings) without steaming it, then soaking or retting it in a pond.
  4. Pound the thicker ends of the switches to loosen the bark.
  5. Strip the bark from the wood. Once started, one’s foot may be used as leverage to complete the stripping process.
  6. Bundle the strips together and then hang them up to air dry. When dried, they can be stored until a sufficient quantity has been gathered to begin the next step in the process. An Israeli papermaker skips ahead to step 8 without drying the strips.
  7. Soak the dried strips for at least 12 hours to soften them.
  8. Using a knife as a scraper (or, as Aimee Lee suggests, an oyster shucking knife), scrape the dark outer bark (the epidermis) from the softer, pale inner bark (the cambium). I’m uncertain if the “endocarp” the narrator refers to is still part of the cambium. Essentially, you remove the dark bark, and keep intact the soft inner layer and the next, slightly more fibrous layer that’s attached to it. In the video above, these are cut to half their original length.
  9. Boil the bundles of pale inner bark in a 12% alkali solution, according to the video above that does not indicate what is used to achieve that exact percentage of alkalinity. Wood ash or soda ash (sodium carbonate – a product generated when baking soda [sodium bicarbonate] is heated to release carbon dioxide – tutorials are to be found online) are two possible options. Other sources do not give specific chemicals or measurements and Li Ziqi shows only that handfuls of ash are added to the cauldron.
  10. Boil the bark in the solution for two hours, turning the mass every 30 minutes to allow for even immersion.
  11. Remove the boiled bark to a container of water and inspect for impurities when it is cool enough to handle.
  12. Beat the fibers with a squared-off hardwood stick or wooden mallets to loosen and separate them. The video above states that the fibers are beaten in passes to the left and right, six times each, then top to bottom, six times each. It seems that between each pass, the lump is recombined after it’s been flattened.
  13. In a vat, add the pulp to a water and neri mixture. Neri is made from a plant called tararo-aoi or sunset (musk)mallow in English (Latin: Abelmoschus manihot). Abelmoschus manihot is in the marshmallow family and is in the same genus a okra, which is sometimes substituted for it. The neri acts as an antiflocculant or dispersant (Aimee Lee calls it a formation aid in the video posted above in the “hanji section”) and as such, it discourages the formation of lumps and assists in the even distribution of the kozo fibers in the water. See the section below for information on neri.
  14. Stir the mixture then prepare the screen that will be used to mold the sheets of paper. In Japan and Korea, these screens are mats made of thin bamboo splints that are woven together. Hanji-maker Aimee Lee, who oversaw the construction of the first hanji-papermaking-studio in the US shows, in this video, the process by which she and several interns designed long-lasting screens made with metal rods woven together in the traditional way. Korea’s last screenmaker demonstrates his process in Lee’s short video, here.
  15. Use the screen to swish the solution (there are specific techniques and of course terms relative to each phase of swishing), gathering up the desired amount of fiber to make paper of the desired thickness
  16. Drain the water and lift the screen off its rack. The paper is then couched (pronounced “cooched”) which entails aligning it very precisely and releasing the fibers onto the stack of already released sheets.
  17. Leave the stack of sheets overnight, then press them to remove excess water.
  18. After pressing, each sheet is peeled off the stack, then laid on a board and brushed to smooth out bubbles and wrinkles.
  19. Take the boards outdoors to sun-dry, or, alternatively, a “drying wall” is used, as in the case of the hanji-making process..
  20. Inspect all sheets for discoloration, holes, or uneven thickness and discard any that have such imperfections.

Coppiced paper mulberry for use in papermaking.,_forestry,_arts,_and_commerce._From_travels_and_researches_undertaken_at_the_cost_of_the_Prussian_government(1889)_(14598161510).jpg


To understand more about neri, the additive in the washi-making process that assures uniform fiber dispersion and therefore allows for a more refined end-product (and one that can be made consistently), I cannot recommend Paul Denhoed’s explanation highly enough.

See Neri (part 1) and Neri (part 2). Additionally, Aimee Lee’s video on the winter hanji-making apprenticeship has a brief description of its preparation.

Produced by pounding and soaking the roots of Abelmoschus manihot, also known by its English common names, sunset hibiscus (no longer classified as a hibiscus, but the name remains) or muskmallow. This plant is in the same family as hollyhocks and marshmallow, though it’s more closely related to okra. Like okra, it produces a mucilaginous ooze. Its roots are pulverized and the mucilage is collected, mixed in water. Reportedly, the winter-harvested roots contain more effective neri.
By © Derek Ramsey /, CC BY-SA 4.0,

This perennial, with its big showy flowers seems to be available commercially and is known to be adapted to the southeast (as is the paper mulberry, so all your raw materials are available and waiting for any of you who live there and want to start making washi!).

In fact, here’s someone in South Carolina doing exactly that (though she’s not using neri and so has to rely on a commercial product).

Additional uses for paper mulberry

Other uses for the very useful and versatile paper mulberry include tapa cloth (used extensively in Polynesia)

As cordage

As food

As a fire-starter

*bibulous adj. 1: highly absorbent 2a: fond of alcoholic beverages 2b: of, relating to, or marked by the consumption of alcoholic beverages. [we can safely assume that the patent above is using the term in its first definition].

Proudfoot, W. B. 1972. The Origin of Stencil Duplicating. London: Hutchinson & Co. To locate a library copy, see

See also Hughes, Sukey. 1978. Washi: The World of Japanese Paper. Tokyo: Kodansha. To locate a library copy, see

For additional information and images of paper mulberry, see the Royal Botanic Garden/Kew’s Plants of the World site, here:

For a one-page write-up on the main raw materials used in washi making, see this document:

2 replies on “Stencil Paper”

I would never have thought of any of these as a source of paper!! Wow, that’s a lot of documentation.

BTW the invasive species thing isn’t just for shouldering out native growth; it’s often for bringing in diseases which the invasive is immune to but that then wipe out native species, sometimes highly significant. This happened to … um, was it American beechnuts?

“Wow, that’s a lot of documentation” – heh, I was kind of swimming in information for awhile there.

I absolutely agree about the disease vector aspect. Sudden oak death, here in CA, was brought in on commercially shipped plants (can’t remember from where), as was huanglongbing, the citrus-greening disease that threatens all the US citrus crops (the vector is actually the Asian citrus psyllid that came in on some something and without it, the greening disease would not have spread). There’s a lantern fly that’s made the headlines lately too – not a disease, but certainly a pest.

Interestingly (well, at least to a plant nerd, lol), CA black walnuts are obviously adapted to native soil pathogens while the old world walnuts are not, so the native is used for rootstock to protect the “invasive-if-you-count-orchards.”

My non-purist streak comes as a response to the fact that plants DO move and they’re opportunists to do so. Some of the freaking out is a warped form of biophilia and a desire to keep ecosystems safely static and unchanging. Don’t get me started on worldwide efforts to remove people from land in an effort to “protect and manage” it. Yes, degradation is one thing, but acting as though any sign of human presence indicates degradation is another.

end of rant 🙂

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