Rag paper

Type	Paper
Material	Fiber crop rags
Introduced	106 CE,China

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Rag paper, orrag-made paper, is a category ofpaper that is made from apulp of discardedtextiles,rope and otherfiber products. Rag paper in its various forms was a widely used paper for most of the past two millennia. Production spread from its origin inChina in the early 2nd century along theSilk Road to theIslamic world by the 8th century, and toChristian Europe by the 12th century.Western Europe came to dominant rag production up through the mid-19th century, when rag paper was rejected in favor of far more cost-efficientpulpwoodacidic paper.

Rag paper is valued today as a specialty paper for its archival quality andtear resistance compared towood pulp paper.^[1][2] Modern rag paper is oftencotton paper, made fromcotton linters, with a usualpH of 6.4 anddegree of polymerization of 1481.2.^[3]

The invention of rag paper is attributed toCai Lun in 106 CE,Luoyang, China, when he beathemp andramie rags with rope scraps,paper mulberry and other fibers into apulp.Dunhuang andTurfan were major centers of rag paper production in the first millennium, possibly due to their desert environment incentivizing rag re-use versusmulberry paper production. Rag paper production declined in China after the 10th century due to the rising cost of textiles.^[4][5]

Rag paper was introduced to the Middle East through theSilk Road prior to the 8th century, but domestic production only began by the 8th century, particularly inBaghdad. Arab papermakers developed 'pure' rag paper, made from an alternativepulp entirely constitutinglinen rags; this paper supplantedpapyrus andparchment for most uses by the 11th century.^{[6][7]: 678}

Some 13th-14th century Muslims were initially skeptical of rag paper imported from Europe, purporting it to breakIslamic dietary laws vis-a-vis Christian worker contamination, as well as objecting to Christianwatermarks.Ibn Marzuq rejected these concerns in afatwa, pointing to the cleaning process and historical alternative writing material use as justifications.^{[8]: 44–46 [9]}

Rag paper spread toAl-Andalus by the mid-10th century, withXàtiva being a major production center of linen rag paper by the 11th century.Sephardic Jews were heavily involved in the rag paper industry. TheReconquista saw Spanish Christians increasingly in possession of libraries of Andalusian paper books, spurring a Western European paper industry utilizingcotton rags in addition to linens.^[10][11]

In the late 12th century, rag paper spread to Italy through Mediterranean trade with themerchant republics.Amalfi paper was a particularly relevant Italian rag paper by the early 13th century; its prevalence as a writing material is marked byFrederick II, Holy Roman Emperor banning its use for court documents, in favor ofparchment.^[12]

Following the invention of theprinting press in the 15th century, the cost of book production dropped significantly, increasing paper demand. This introduced rag shortages for producers in Italy and Holland, and a rag export market demand for less urban regions likePortugal and theNew World colonies. Rag exporters and local paper mills competed for a limited rag supply, like in theRepublic of Lucca, a major rag paper production center: a late-16th century rag shortage led to conflict between rag exporters and local paper mills, leading to a 1695 accord to regulate the rag export market.^[13]

Printing press production speeds did not significantly increase until the 1812 invention of the steam-powered printing press byFriedrich Koenig. Conversely, the 1799 invention of thepaper machine mechanized the rag paper industry.^[14]

As theIndustrial Revolution spread, Western Europe became the major exporters of rag paper, enjoying ample rag supply from urban centerragpickers andindustrial textile production. TheOttoman Empire's domestic paper industry collapsed over the course of the late 18th century, succumbing to rag shortages and European price competition.^[8] The nascent American rag paper industry struggled to meet rag demand as well, as colonists could not be dissuaded from keeping rags for their own use; states and industrialists implored people to keep 'rag bags' to increase supplies.^{[15]: 59–67}

The 1844 invention of therotary printing press and the rise ofliteracy in industrialized nations increased demand for and output of print products. As the rag paper print economy hit its zenith in the 1850s, even Western European industrial paper producers struggled to meet paper demand as it outpaced domestic rag-picking. In the United Kingdom,excise taxes on rags coupled with foreign demand for rag exports particularly bottle-necked the British rag paper industry; producers attempted to increase supply by bleaching colored rags, andhousemaids were implored to sell their spare rags instead of keeping them asmenstrual rags. TheLondon Times put out a bounty in 1855 for£1,000 for an alternative to rag paper.^[14][16][17]

In the United States, rag shortages continued from the 18th century through thePanic of 1837, incentivizing experiments with alternativenatural fibers.Corn husk paper,straw paper, andManila hemp paper were notable alternatives invented in the first half of the 19th century, but the standard American industrial pulp remained imported European linen rags cut with raw domesticcotton.^{[15]: Ch.11}

With the introduction ofesparto grass paper in the 1860s andacidic paper in the later 19th century, rag-paper became increasingly economically obsolete. Newspapers were greatly incentivized to shift tonewsprint, to minimize printing costs; however, archival quality suffered immensely due toslow fire decay.^[17][18]

Kier for ragscouring

Schematic of industrial rag breaker

Rag-pickers would collect rags from urban areas to sell to producers, which would in turn make rag paper for sale back to city centers. Collected rags were cut, thenscoured to remove impurities. The washed rags are ground into apulp, then the pulp made into aslurry before screening,sizing and drying.^[16][15]

Industrialized rag paper production saw the introduction ofpaper machines,kiers, mechanical washers, and mountedscythe workstations to process larger amounts of rags.^[15]

• Amalfi paper
• Cai Hou paper
• India paper
• Xuan paper

• Cotton paper
• Pulpwood
• Second Industrial Revolution

• Paper
• Papermaking
• Papermaking in the United Kingdom
• Papermaking in China
• Papermaking in the United States
• Cotton industry
• Linen industry
• 2nd-century introductions

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