Author: jeanclaus.online

  • Origami 

    Origami (折り紙, Japanese pronunciation: [oɾiɡami] or [oɾiꜜɡami], from ori meaning “folding”, and kami meaning “paper” (kami changes to gami due to rendaku)) is the Japanese art of paper folding. In modern usage, the word “origami” is often used as an inclusive term for all folding practices, regardless of their culture of origin. The goal is to transform a flat square sheet of paper into a finished sculpture through folding and sculpting techniques. Modern origami practitioners generally discourage the use of cuts, glue, or markings on the paper. Origami folders often use the Japanese word kirigami to refer to designs which use cuts.

    In the detailed Japanese classification, origami is divided into stylized ceremonial origami (儀礼折り紙, girei origami) and recreational origami (遊戯折り紙, yūgi origami), and only recreational origami is generally recognized as origami.[1][2] In Japan, ceremonial origami is generally called “origata” (ja:折形) to distinguish it from recreational origami. The term “origata” is one of the old terms for origami.[3][4][5]

    The small number of basic origami folds can be combined in a variety of ways to make intricate designs. The best-known origami model is the Japanese paper crane. In general, these designs begin with a square sheet of paper whose sides may be of different colors, prints, or patterns. Traditional Japanese origami, which has been practiced since the Edo period (1603–1868), has often been less strict about these conventions, sometimes cutting the paper or using nonsquare shapes to start with. The principles of origami are also used in stentspackaging, and other engineering applications.[6][7]

    Etymology

    The word “origami” is a compound of two smaller words: “ori” (root verb “oru”), meaning to fold, and “kami”, meaning paper. Until recently, not all forms of paper folding were grouped under the word origami. Before that, paper folding for play was known by a variety of names, including “orikata” or “origata” (折形), “orisue” (折据), “orimono” (折物), “tatamigami” (畳紙) and others.[5][8]

    History

    Main article: History of origami

    The folding of two origami cranes linked together, from the first known technical book on origami, Hiden senbazuru orikata, published in Japan in 1797

    Distinct paperfolding traditions arose in Europe, China, and Japan which have been well-documented by historians. These seem to have been mostly separate traditions, until the 20th century.

    Ceremonial origami (origata)

    By the 7th century, paper had been introduced to Japan from China via the Korean Peninsula, and the Japanese developed washi by improving the method of making paper in the Heian period. The papermaking technique developed in Japan around 805 to 809 was called nagashi-suki (流し漉き), a method of adding mucilage to the process of the conventional tame-suki (溜め漉き) technique to form a stronger layer of paper fibers.[1][2][9][10] With the development of Japanese papermaking technology and the widespread use of paper, folded paper began to be used for decorations and tools for religious ceremonies such as goheiōnusa (ja:大麻 (神道)) and shide at Shinto shrines. Religious decorations made of paper and the way gifts were wrapped in folded paper gradually became stylized and established as ceremonial origami.[1][2] During the Heian period, the Imperial court established a code of etiquette for wrapping money and goods used in ceremonies with folded paper, and a code of etiquette for wrapping gifts.[3]

    A modern ceremonial origami (origata) that follows the ceremonial origami of the upper samurai class of the Muromachi period

    In the Muromachi period from the 1300s to the 1400s, various forms of decorum were developed by the Ogasawara clan and Ise clans (ja:伊勢氏), completing the prototype of Japanese folded-paper decorum that continues to this day. The Ise clan presided over the decorum of the inside of the palace of the Ashikaga Shogunate, and in particular, Ise Sadachika (ja:伊勢貞親) during the reign of the eighth Shogun, Ashikaga Yoshimasa (足利義政), greatly influenced the development of the decorum of the daimyo and samurai classes, leading to the development of various stylized forms of ceremonial origami. The shapes of ceremonial origami created in this period were geometric, and the shapes of noshi to be attached to gifts at feasts and weddings, and origami that imitated butterflies to be displayed on sake vessels, were quite different from those of later generations of recreational origami whose shapes captured the characteristics of real objects and living things. The “noshi” wrapping, and the folding of female and male butterflies, which are still used for weddings and celebrations, are a continuation and development of a tradition that began in the Muromachi period.[1][2][11] A reference in a poem by Ihara Saikaku from 1680 describes the origami butterflies used during Shinto weddings to represent the bride and groom.[12]

    Recreational origami

    1500s-1800s

    It is not certain when play-made paper models, now commonly known as origami, began in Japan. However, the kozuka of a Japanese sword made by Gotō Eijō (後藤栄乗) between the end of the 1500s and the beginning of the 1600s was decorated with a picture of a crane made of origami, and it is believed that origami for play existed by the Sengoku period or the early Edo period.[5]

    In 1747, during the Edo period, a book titled Ranma zushiki (欄間図式) was published, which contained various designs of the ranma (ja:欄間), a decoration of Japanese architecture. This included origami of various designs, including paper models of cranes, which are still well known today. It is thought that by this time, many people were familiar with origami for play, which modern people recognize as origami. During this period, origami was commonly called orikata (折形) or orisue (折据) and was often used as a pattern on kimonos and decorations.[5]

    Hyakkaku (百鶴, One hundred cranes) is one of the works featured in Hiden senbazuru orikata. It is made by folding a single sheet of paper, and its production method has been designated an Intangible Cultural Property of Kuwana City.

    Hiden senbazuru orikata (ja:秘傳千羽鶴折形), published in 1797, is the oldest known technical book on origami for play. The book contains 49 origami pieces created by a Buddhist monk named Gidō (:ja:義道) in Ise Province, whose works were named and accompanied by kyōka (狂歌, comic tanka) by author Akisato Ritō (秋里籬島). These pieces were far more technically advanced than their predecessors, suggesting that origami culture had become more sophisticated. Gido continued to produce origami after the publication of his book, leaving at least 158 highly skilled masterpieces for posterity. In 1976, Kuwana City in Mie Prefecture, Gido’s hometown, designated 49 of the methods described in the Hiden senbazuru orikata as Intangible Cultural Properties of Kuwana City. Kuwana City has also certified qualified persons who are able to correctly produce these works and have in-depth knowledge of the art. Kuwana City has published some of the origami production methods on YouTube.[13][14][15]

    From the late Edo period to the Bakumatu period, origami that imitated the six legendary Japanese poets, rokkasen (六歌仙) listed in the Kokin Wakashū (古今和歌集) compiled in the 900s and the characters in Chūshingura became popular, but today they are rarely used as subjects for origami.[13]

    In Europe, there was a well-developed genre of napkin folding, which flourished during the 17th and 18th centuries. After this period, this genre declined and was mostly forgotten; historian Joan Sallas attributes this to the introduction of porcelain, which replaced complex napkin folds as a dinner-table status symbol among nobility.[16] However, some of the techniques and bases associated with this tradition continued to be a part of European culture; folding was a significant part of Friedrich Fröbel‘s “Kindergarten” method, and the designs published in connection with his curriculum are stylistically similar to the napkin fold repertoire. Another example of early origami in Europe is the “pajarita,” a stylized bird whose origins date from at least the nineteenth century.[17]

    Since 1800s

    When Japan opened its borders in the 1860s, as part of a modernization strategy, they imported Fröbel’s Kindergarten system—and with it, German ideas about paperfolding. This included the ban on cuts, and the starting shape of a bicolored square. These ideas, and some of the European folding repertoire, were integrated into the Japanese tradition. Before this, traditional Japanese sources use a variety of starting shapes, often had cuts, and if they had color or markings, these were added after the model was folded.[18] In Japan, the first kindergarten was established in 1875, and origami was promoted as part of early childhood education. The kindergarten’s 1877 regulations listed 25 activities, including origami subjects. Shōkokumin (小国民), a magazine for boys, frequently published articles on origami. Origami Zusetsu (折紙図説), published in 1908, clearly distinguished ceremonial origami from recreational origami. These books and magazines carried both the traditional Japanese style of origami and the style inspired by Fröbel.[8]

    In the early 1900s, Akira YoshizawaKosho Uchiyama, and others began creating and recording original origami works. Akira Yoshizawa in particular was responsible for a number of innovations, such as wet-folding and the Yoshizawa–Randlett diagramming system, and his work inspired a renaissance of the art form.[19]

    In 1974, origami was offered in the USSR as an additional activity for elementary school children.[20]

    During the 1980s a number of folders started systematically studying the mathematical properties of folded forms, which led to a rapid increase in the complexity of origami models.[21]

    Starting in the late 20th century, there has been a renewed interest in understanding the behavior of folding matter, both artistically and scientifically. The “new origami,” which distinguishes it from old craft practices, has had a rapid evolution due to the contribution of computational mathematics and the development of techniques such as box-pleatingtessellations and wet-folding. Artists like Robert J. LangErik DemaineSipho MabonaGiang DinhPaul Jackson, and others, are frequently cited for advancing new applications of the art. The computational facet and the interchanges through social networks, where new techniques and designs are introduced, have raised the profile of origami in the 21st century.[22][23][24]

    Techniques and materials

    Techniques

    A list of nine basic origami folds: the valley (or mountain), the pleat, the rabbit ear, the outside reverse, the inside reverse, the crimp, the squash, the sink and the petal

    Main article: Yoshizawa–Randlett system

    Many origami books begin with a description of basic origami techniques which are used to construct the models. This includes simple diagrams of basic folds like valley and mountain folds, pleats, reverse folds, squash folds, and sinks. There are also standard named bases which are used in a wide variety of models, for instance the bird base is an intermediate stage in the construction of the flapping bird.[25] Additional bases are the preliminary base (square base), fish base, waterbomb base, and the frog base.[26]

    Origami paper

    Main article: Origami paper

    crane and papers of the same size used to fold it

    Almost any laminar (flat) material can be used for folding; the only requirement is that it should hold a crease.

    Origami paper, often referred to as “kami” (Japanese for paper), is sold in prepackaged squares of various sizes ranging from 2.5 cm (1 in) to 25 cm (10 in) or more. It is commonly colored on one side and white on the other; however, dual coloured and patterned versions exist and can be used effectively for color-changed models. Origami paper weighs slightly less than copy paper, making it suitable for a wider range of models.

    Normal copy paper with weights of 70–90 g/m2 (19–24 lb) can be used for simple folds, such as the crane and waterbomb. Heavier weight papers of 100 g/m2 (approx. 25 lb) or more can be wet-folded. This technique allows for a more rounded sculpting of the model, which becomes rigid and sturdy when it is dry.

    Foil-backed paper, as its name implies, is a sheet of thin foil glued to a sheet of thin paper. Related to this is tissue foil, which is made by gluing a thin piece of tissue paper to kitchen aluminium foil. A second piece of tissue can be glued onto the reverse side to produce a tissue/foil/tissue sandwich. Foil-backed paper is available commercially, but not tissue foil; it must be handmade. Both types of foil materials are suitable for complex models.

    Washi (和紙) is the traditional origami paper used in Japan. Washi is generally tougher than ordinary paper made from wood pulp, and is used in many traditional arts. Washi is commonly made using fibres from the bark of the gampi tree, the mitsumata shrub (Edgeworthia papyrifera), or the paper mulberry but can also be made using bamboohemp, rice, and wheat.

    Artisan papers such as unryu, lokta, hanji[citation needed], gampi, kozo, saa, and abaca have long fibers and are often extremely strong. As these papers are floppy to start with, they are often backcoated or resized with methylcellulose or wheat paste before folding. Also, these papers are extremely thin and compressible, allowing for thin, narrowed limbs as in the case of insect models.

    Paper money from various countries is also popular to create origami with; this is known variously as Dollar Origami, Orikane, and Money Origami.

    Tools

    Bone folders

    It is common to fold using a flat surface, but some folders like doing it in the air with no tools, especially when displaying the folding.[citation needed] Some folders believe that no tool should be used when folding.[citation needed] However a couple of tools can help especially with the more complex models. For instance a bone folder allows sharp creases to be made in the paper easily, paper clips can act as extra pairs of fingers, and tweezers can be used to make small folds. When making complex models from origami crease patterns, it can help to use a ruler and ballpoint embosser to score the creases. Completed models can be sprayed so that they keep their shape better, and a spray is needed when wet folding.

    Types

    Action origami

    Main article: Action origami

    In addition to the more common still-life origami, there are also moving object designs; origami can move. Action origami includes origami that flies, requires inflation to complete, or, when complete, uses the kinetic energy of a person’s hands, applied at a certain region on the model, to move another flap or limb. Some argue that, strictly speaking, only the latter is really “recognized” as action origami. Action origami, first appearing with the traditional Japanese flapping bird, is quite common. One example is Robert Lang‘s instrumentalists; when the figures’ heads are pulled away from their bodies, their hands will move, resembling the playing of music.

    Modular origami

    stellated icosahedron made from custom papers

    Main article: Modular origami

    Modular origami consists of putting a number of identical pieces together to form a complete model. Often the individual pieces are simple, but the final assembly may be more difficult. Many modular origami models are decorative folding balls such as kusudama, which differ from classical origami in that the pieces may be held together using thread or glue.

    Chinese paper folding, a cousin of origami, includes a similar style called golden venture folding where large numbers of pieces are put together to create elaborate models. This style is most commonly known as “3D origami”. However, that name did not appear until Joie Staff published a series of books titled 3D OrigamiMore 3D Origami, and More and More 3D Origami.[citation needed] This style originated from some Chinese refugees while they were detained in America and is also called Golden Venture folding from the ship they came on.[citation needed]

    Wet-folding

    Main article: Wet-folding

    Wet-folding is an origami technique for producing models with gentle curves rather than geometric straight folds and flat surfaces. The paper is dampened so it can be moulded easily, and the final model keeps its shape when it dries. It can be used, for instance, to produce very natural looking animal models. Size, an adhesive that is crisp and hard when dry, but dissolves in water when wet and becoming soft and flexible, is often applied to the paper either at the pulp stage while the paper is being formed, or on the surface of a ready sheet of paper. The latter method is called external sizing and most commonly uses Methylcellulose, or MC, paste, or various plant starches.

    Pureland origami

    Main article: Pureland origami

    Pureland origami adds the restrictions that only simple mountain/valley folds may be used, and all folds must have straightforward locations. It was developed by John Smith in the 1970s to help inexperienced folders or those with limited motor skills. Some designers also like the challenge of creating within the very strict constraints.

    Origami tessellations

    Origami tessellation is a branch that has grown in popularity after 2000. A tessellation is a collection of figures filling a plane with no gaps or overlaps. In origami tessellations, pleats are used to connect molecules such as twist folds together in a repeating fashion. During the 1960s, Shuzo Fujimoto was the first to explore twist fold tessellations in any systematic way, coming up with dozens of patterns and establishing the genre in the origami mainstream. Around the same time period, Ron Resch patented some tessellation patterns as part of his explorations into kinetic sculpture and developable surfaces, although his work was not known by the origami community until the 1980s. Chris Palmer is an artist who has extensively explored tessellations after seeing the Zilij patterns in the Alhambra, and has found ways to create detailed origami tessellations out of silk. Robert Lang and Alex Bateman are two designers who use computer programs to create origami tessellations. The first international convention devoted to origami tessellations was hosted in Brasília (Brazil) in 2006,[27] and the first instruction book on tessellation folding patterns was published by Eric Gjerde in 2008.[28] Since then, the field has grown very quickly. Tessellation artists include Polly Verity (Scotland); Joel Cooper, Christine Edison, Ray Schamp and Goran Konjevod from the US; Roberto Gretter (Italy); Christiane Bettens (Switzerland); Carlos Natan López (Mexico); and Jorge C. Lucero (Brazil).

    Kirigami

    Main article: Kirigami

    Kirigami is a Japanese term for paper cutting. Cutting was often used in traditional Japanese origami, but modern innovations in technique have made the use of cuts unnecessary. Most origami designers no longer consider models with cuts to be origami, instead using the term Kirigami to describe them. This change in attitude occurred during the 1960s and 70s, so early origami books often use cuts, but for the most part they have disappeared from the modern origami repertoire, and most modern books do not even mention cutting.[29]

    Strip folding

    Strip folding is a combination of paper folding and paper weaving.[30] A common example of strip folding is called the Lucky Star, also called Chinese lucky star, dream star, wishing star, or simply origami star. Another common fold is the Moravian star which is made by strip folding in a 3-dimensional design to include 16 spikes.[30]

    Teabag folding

    Example of folded “tea bag” paper

    Teabag folding is credited to Dutch artist Tiny van der Plas, who developed the technique in 1992 as a papercraft art for embellishing greeting cards. It uses small square pieces of paper (e.g., a tea bag wrapper) bearing symmetrical designs that are folded in such a way that they interlock and produce a three-dimensional version of the underlying design. The basic kite fold is used to produce rosettes that are a 3 dimensional version of the 2D design.

    The basic rosette design requires eight matching squares to be folded into the ‘kite’ design. Mathematics teachers find the designs very useful as a practical way of demonstrating some basic properties of symmetry.[citation needed]

    Mathematics and technical origami

    Mathematics and practical applications

    Spring Into Action, designed by Jeff Beynon, made from a single rectangular piece of paper[31]

    Main article: Mathematics of paper folding

    The practice and study of origami encapsulates several subjects of mathematical interest. For instance, the problem of flat-foldability (whether a crease pattern can be folded into a 2-dimensional model) has been a topic of considerable mathematical study.

    A number of technological advances have come from insights obtained through paper folding. For example, techniques have been developed for the deployment of car airbags and stent implants from a folded position.[32]

    The problem of rigid origami (“if we replaced the paper with sheet metal and had hinges in place of the crease lines, could we still fold the model?”) has great practical importance. For example, the Miura map fold is a rigid fold that has been used to deploy large solar panel arrays for space satellites.

    Origami can be used to construct various geometrical designs not possible with compass and straightedge constructions. For instance paper folding may be used for angle trisection and doubling the cube.

    Technical origami

    Technical origami, known in Japanese as origami sekkei (折り紙設計), is an origami design approach in which the model is conceived as an engineered crease pattern, rather than developed through trial-and-error. With advances in origami mathematics, the basic structure of a new origami model can be theoretically plotted out on paper before any actual folding even occurs. This method of origami design was developed by Robert LangMeguro Toshiyuki and others, and allows for the creation of extremely complex multi-limbed models such as many-legged centipedes, human figures with a full complement of fingers and toes, and the like.

    The crease pattern is a layout of the creases required to form the structure of the model. Paradoxically enough, when origami designers come up with a crease pattern for a new design, the majority of the smaller creases are relatively unimportant and added only towards the completion of the model. What is more important is the allocation of regions of the paper and how these are mapped to the structure of the object being designed. By opening up a folded model, you can observe the structures that comprise it; the study of these structures led to a number of crease-pattern-oriented design approaches

    The pattern of allocations is referred to as the ‘circle-packing’ or ‘polygon-packing’. Using optimization algorithms, a circle-packing figure can be computed for any uniaxial base of arbitrary complexity.[33] Once this figure is computed, the creases which are then used to obtain the base structure can be added. This is not a unique mathematical process, hence it is possible for two designs to have the same circle-packing, and yet different crease pattern structures.

    As a circle encloses the maximum amount of area for a given perimeter, circle packing allows for maximum efficiency in terms of paper usage. However, other polygonal shapes can be used to solve the packing problem as well. The use of polygonal shapes other than circles is often motivated by the desire to find easily locatable creases (such as multiples of 22.5 degrees) and hence an easier folding sequence as well. One popular offshoot of the circle packing method is box-pleating, where squares are used instead of circles. As a result, the crease pattern that arises from this method contains only 45 and 90 degree angles, which often makes for a more direct folding sequence.

    A number of computer aids to origami such as TreeMaker and Oripa, have been devised.[34] TreeMaker allows new origami bases to be designed for special purposes[35] and Oripa tries to calculate the folded shape from the crease pattern.[36]

    Copyright in origami designs and the use of models has become an increasingly important issue in the origami community, as the internet has made the sale and distribution of pirated designs very easy.[37] It is considered good etiquette to always credit the original artist and the folder when displaying origami models. It has been claimed that all commercial rights to designs and models are typically reserved by origami artists; however, the degree to which this can be enforced has been disputed. Under such a view, a person who folds a model using a legally obtained design could publicly display the model unless such rights were specifically reserved, whereas folding a design for money or commercial use of a photo for instance would require consent.[38] The Origami Authors and Creators group was set up to represent the copyright interests of origami artists and facilitate permissions requests.

    However, a court in Japan has asserted that the folding method of an origami model “comprises an idea and not a creative expression, and thus is not protected under the copyright law”.[39] Further, the court stated that “the method to folding origami is in the public domain; one cannot avoid using the same folding creases or the same arrows to show the direction in which to fold the paper”. Therefore, it is legal to redraw the folding instructions of a model of another author even if the redrawn instructions share similarities to the original ones, as long as those similarities are “functional in nature”. The redrawn instructions may be published (and even sold) without necessity of any permission from the original author.

    Origami in various meanings

    A Japanese sword authentication paper (Origami) from 1702 that Hon’ami Kōchū certified a tantō made by Yukimitsu in the 14th century as authentic

    From a global perspective, the term ‘origami’ refers to the folding of paper to shape objects for entertainment purposes, but it has historically been used in various ways in Japan. For example, the term ‘origami’ also refers to the certificate of authenticity that accompanies a Japanese sword or tea utensil. The people of the Hon’ami clan, who were the authority on Japanese sword appraisal from the Muromachi period to the Edo period, responded to the requests of the shogundaimyo and samurai by appraising Japanese swords, determining when and by which school the sword was made, whether the inscription on the nakago was genuine or not, and what the price was, and then issuing origami with the results written on it. This has led to the Japanese word ‘origami tsuki’ (折り紙付き) meaning ‘origami is attached’ meaning that the quality of the object or the ability of the person is sufficiently high.[40]

    The term ‘origami’ also referred to a specific style of old documents in Japan. The paper folded vertically is called ‘tategami’ (竪紙), while the paper folded horizontally is called ‘origami’, and origami has a lower status than tategami. This style of letter began to be used at the end of the Heian period, and in the Kamakura period it was used as a complaint, and origami came to refer to the complaint itself. Furthermore, during the Muromachi period, origami was often used as a command document or a catalog of gifts, and it came to refer to the catalog of gifts itself.[41]

    These pictures show examples of various types of origami.

  • Paper

    Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from woodragsgrassesherbivore dung, or other vegetable sources in water. Once the water is drained through a fine mesh leaving the fibre evenly distributed on the surface, it can be pressed and dried.

    The papermaking process developed in east Asia, probably China, at least as early as 105 CE,[1] by the Han court eunuch Cai Lun, although the earliest archaeological fragments of paper derive from the 2nd century BCE in China.[2]

    Although paper was originally made in single sheets by hand, today it is mass-produced on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year.[not verified in body] It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency, and security paper, or in a number of industrial and construction processes.

    History

    Main article: History of paper

    Hemp wrapping paper, China, c. 100 BCE

    The oldest known archaeological fragments of the immediate precursor to modern paper date to the 2nd century BCE in China. The pulp papermaking process is ascribed to Cai Lun, a 2nd-century CE Han court eunuch.[2]

    It has been said that knowledge of papermaking was passed to the Islamic world after the Battle of Talas in 751 CE when two Chinese papermakers were captured as prisoners and used to extract ‘the secrets’ of papermaking. Although the veracity of this story is uncertain, paper started to be made in Samarkand soon after.[3] In the 13th century, the knowledge and uses of paper spread from the Middle East to medieval Europe, where the first water-powered paper mills were built.[4] Because paper was introduced to the West through the city of Baghdad, it was first called bagdatikos.[5] In the 19th century, industrialization greatly reduced the cost of manufacturing paper. In 1844, the Canadian inventor Charles Fenerty and the German inventor Friedrich Gottlob Keller independently developed processes for pulping wood fibres.[6]

    Early sources of fibre

    See also: wood pulpdeinking, and pulpwood

    Before the industrialisation of paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemplinen and cotton.[7] A process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774.[7] Today this method is called deinking. It was not until the introduction of wood pulp in 1843 that paper production was not dependent on recycled materials from ragpickers.[7]

    Etymology

    Further information: Papyrus

    The word paper is etymologically derived from Latin papyrus, which comes from the Greek πᾰ́πῡρος (pápūros), the word for the Cyperus papyrus plant.[8][9] Papyrus is a thick, paper-like material produced from the pith of the Cyperus papyrus plant, which was used in ancient Egypt and other Mediterranean cultures for writing before the introduction of paper.[10] Although the word paper is etymologically derived from papyrus, the two are produced very differently and the development of the first is distinct from the development of the second. Papyrus is a lamination of natural plant fibre, while paper is manufactured from fibres whose properties have been changed by maceration.[2]

    Papermaking

    Main article: Papermaking

    Chemical pulping

    Main articles: Kraft processsulfite process, and soda pulping

    To make pulp from wood, a chemical pulping process separates lignin from cellulose fibre. A cooking liquor is used to dissolve the lignin, which is then washed from the cellulose; this preserves the length of the cellulose fibres. Paper made from chemical pulps are also known as wood-free papers (not to be confused with tree-free paper); this is because they do not contain lignin, which deteriorates over time. The pulp can also be bleached to produce white paper, but this consumes 5% of the fibres. Chemical pulping processes are not used to make paper made from cotton, which is already 90% cellulose.

    The microscopic structure of paper: Micrograph of paper autofluorescing under ultraviolet illumination. The individual fibres in this sample are around 10 μm in diameter.

    There are three main chemical pulping processes: the sulfite process dates back to the 1840s and was the dominant method before the second world war. The kraft process, invented in the 1870s and first used in the 1890s, is now the most commonly practised strategy; one of its advantages is the chemical reaction with lignin produces heat, which can be used to run a generator. Most pulping operations using the kraft process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents. Soda pulping is another specialty process used to pulp strawsbagasse and hardwoods with high silicate content.

    Mechanical pulping

    There are two major mechanical pulps: thermomechanical pulp (TMP) and groundwood pulp (GW). In the TMP process, wood is chipped and then fed into steam-heated refiners, where the chips are squeezed and converted to fibres between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres. Mechanical pulping does not remove the lignin, so the yield is very high, > 95%; however, lignin causes the paper thus produced to turn yellow and become brittle over time. Mechanical pulps have rather short fibres, thus producing weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than the chemical kind.

    De-inked pulp

    Paper recycling processes can use either chemically or mechanically produced pulp; by mixing it with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre for the sake of quality; generally speaking, de-inked pulp is of the same quality or lower than the collected paper it was made from.

    There are three main classifications of recycled fibre:

    • Mill broke or internal mill waste – This incorporates any substandard or grade-change paper made within the paper mill itself, which then goes back into the manufacturing system to be re-pulped back into paper. Such out-of-specification paper is not sold and is therefore often not classified as genuine reclaimed recycled fibre; however most paper mills have been reusing their own waste fibre for many years, long before recycling became popular.
    • Preconsumer waste – This is offcut and processing waste, such as guillotine trims and envelope blank waste; it is generated outside the paper mill and could potentially go to landfill, and is a genuine recycled fibre source; it includes de-inked preconsumer waste (recycled material that has been printed but did not reach its intended end use, such as waste from printers and unsold publications).[11]
    • Postconsumer waste – This is fibre from paper that has been used for its intended end use and includes office waste, magazine papers and newsprint. As the vast majority of this material has been printed – either digitally or by more conventional means such as lithography or rotogravure – it will either be recycled as printed paper or go through a de-inking process first.

    Recycled papers can be made from 100% recycled materials or blended with virgin pulp, although they are (generally) not as strong nor as bright as papers made from the latter.

    Additives

    Besides the fibres, pulps may contain fillers such as chalk or china clay,[12] which improve its characteristics for printing or writing.[13] Additives for sizing purposes may be mixed with it or applied to the paper web later in the manufacturing process; the purpose of such sizing is to establish the correct level of surface absorbency to suit ink or paint.

    Producing paper

    Main articles: Paper machine and papermaking

    Paper mill in Mänttä-VilppulaFinland

    The pulp is fed to a paper machine, where it is formed as a paper web and the water is removed from it by pressing and drying.

    Pressing the sheet removes the water by force. Once the water is forced from the sheet, a special kind of felt, which is not to be confused with the traditional one, is used to collect the water. When making paper by hand, a blotter sheet is used instead.

    Drying involves using air or heat to remove water from the paper sheets. In the earliest days of papermaking, this was done by hanging the sheets like laundry; in more modern times, various forms of heated drying mechanisms are used. On the paper machine, the most common is the steam-heated can dryer. These can reach temperatures above 93 °C (200 °F) and are used in long sequences of more than forty cans where the heat produced by these can easily dry the paper to less than six percent moisture.

    Finishing

    Lower quality paper (used to print the book in 1991) with visible bits of wood

    The paper may then undergo sizing to alter its physical properties for use in various applications.

    Paper at this point is uncoatedCoated paper has a thin layer of material such as calcium carbonate or china clay applied to one or both sides in order to create a surface more suitable for high-resolution halftone screens. (Uncoated papers are rarely suitable for screens above 150 lpi.) Coated or uncoated papers may have their surfaces polished by calendering. Coated papers are divided into matte, semi-matte or silk, and gloss. Gloss papers give the highest optical density in the printed image.

    The paper is then fed onto reels if it is to be used on web printing presses, or cut into sheets for other printing processes or other purposes. The fibres in the paper basically run in the machine direction. Sheets are usually cut “long-grain”, i.e. with the grain parallel to the longer dimension of the sheet. Continuous form paper (or continuous stationery) is cut to width with holes punched at the edges, and folded into stacks.

    Paper grain

    All paper produced by paper machines such as the Fourdrinier Machine are wove paper, i.e. the wire mesh that transports the web leaves a pattern that has the same density along the paper grain and across the grain. Textured finishes, watermarks and wire patterns imitating hand-made laid paper can be created by the use of appropriate rollers in the later stages of the machine.

    Wove paper does not exhibit “laidlines”, which are small regular lines left behind on paper when it was handmade in a mould made from rows of metal wires or bamboo. Laidlines are very close together. They run perpendicular to the “chainlines”, which are further apart. Handmade paper similarly exhibits “deckle edges”, or rough and feathery borders.[14]

    Applications

    Paper money from different countries

    Paper can be produced with a wide variety of properties, depending on its intended use.

    Published, written, or informational items

    • For representing valuepaper moneybank notechequesecurity (see security paper), voucherticket
    • For storing informationbooknotebookgraph paperpunched cardphotographic paper
    • For published materials, publications, and reading materials: books, newspapers, magazines, posters, pamphlets, maps, signs, labels, advertisements, billboards.
    • For individual usediary, notebooks, writing pads, memo pads journals, planners, note to remind oneself, etc.; for temporary personal use: scratch paper
    • For business and professional use: copier paper, ledger paper, typing paper, computer printer paper. Specialized paper for forms and documents such as invoices, receipts, tickets, vouchers, bills, contracts, official forms, agreements.
    • For communication: between individuals and/or groups of people: letter, post cards, airmail, telegrams, newsprintcard stock
    • For organizing and sending documents: envelopes, file folders, packaging, pocket folders, partition folders.
    • For artistic works and uses; drawing paper, pastels, water color paintings, sketch padscharcoal drawings,
    • For special printed items using more elegant forms of paper; stationery, parchment,

    Packaging and industrial uses

    It is estimated that paper-based storage solutions captured 0.33% of the total in 1986 and only 0.007% in 2007, even though in absolute terms the world’s capacity to store information on paper increased from 8.7 to 19.4 petabytes.[15] It is estimated that in 1986 paper-based postal letters represented less than 0.05% of the world’s telecommunication capacity, with sharply decreasing tendency after the massive introduction of digital technologies.[15]

    Paper has a major role in the visual arts. It is used by itself to form two- and three-dimensional shapes and collages.[16][17] It has also evolved to being a structural material used in furniture design.[18] Watercolor paper has a long history of production and use.

    Types, thickness and weight

    Main articles: Paper sizeGrammage, and Paper density

    Card and paper stock for crafts use comes in a wide variety of textures and colors.

    The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch in the United States and in micrometres (μm) in the rest of the world.[19] Paper may be between 0.07 and 0.18 millimetres (0.0028 and 0.0071 in) thick.[20]

    Paper is often characterized by weight. In the United States, the weight is the weight of a ream (bundle of 500 sheets) of varying “basic sizes” before the paper is cut into the size it is sold to end customers. For example, a ream of 20 lb, 8.5 in × 11 in (216 mm × 279 mm) paper weighs 5 pounds because it has been cut from larger sheets into four pieces.[21] In the United States, printing paper is generally 20 lb, 24 lb, 28 lb, or 32 lb at most. Cover stock is generally 68 lb, and 110 lb or more is considered card stock.

    In Europe and other regions using the ISO 216 paper-sizing system, the weight is expressed in grams per square metre (g/m2 or usually gsm) of the paper. Printing paper is generally between 60 gsm and 120 gsm. Anything heavier than 160 gsm is considered card. The weight of a ream therefore depends on the dimensions of the paper and its thickness.

    Most commercial paper sold in North America is cut to standard paper sizes based on customary units and is defined by the length and width of a sheet of paper.

    The ISO 216 system used in most other countries is based on the surface area of a sheet of paper, not on a sheet’s width and length. It was first adopted in Germany in 1922 and generally spread as nations adopted the metric system. The largest standard size paper is A0 (A zero), measuring one square metre (approx. 1189 × 841 mm). A1 is half the size of a sheet of A0 (i.e., 594 mm × 841 mm), such that two sheets of A1 placed side by side are equal to one sheet of A0. A2 is half the size of a sheet of A1, and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets).

    The density of paper ranges from 250 kg/m3 (16 lb/cu ft) for tissue paper to 1500 kg/m3 (94 lb/cu ft) for some specialty paper. Printing paper is about 800 kg/m3 (50 lb/cu ft).[22]

    Paper may be classified into seven categories:[23]

    • Printing papers of wide variety.
    • Wrapping papers for the protection of goods and merchandise. This includes wax and kraft papers.
    • Writing paper suitable for stationery requirements. This includes ledger, bank, and bond paper.
    • Blotting papers containing little or no size.
    • Drawing papers usually with rough surfaces used by artists and designers, including cartridge paper.
    • Handmade papers including most decorative papers, Ingres papersJapanese paper and tissues, all characterized by lack of grain direction.
    • Specialty papers including cigarette paper, toilet tissue, and other industrial papers.

    Some paper types include:

    Paper stability

    A book printed in 1920 on acidic paper, now disintegrating a hundred years later.

    Much of the early paper made from wood pulp contained significant amounts of alum, a variety of aluminium sulfate salt that is significantly acidic. Alum was added to paper to assist in sizing,[24] making it somewhat water resistant so that inks did not “run” or spread uncontrollably. Early papermakers did not realize that the alum they added liberally to cure almost every problem encountered in making their product would be eventually detrimental.[25] The cellulose fibres that make up paper are hydrolyzed by acid, and the presence of alum eventually degrades the fibres until the acidic paper disintegrates in a process known as “slow fire“. Documents written on rag paper are significantly more stable. The use of non-acidic additives to make paper is becoming more prevalent, and the stability of these papers is less of an issue.

    Paper made from mechanical pulp contains significant amounts of lignin, a major component in wood. In the presence of light and oxygen, lignin reacts to give yellow materials,[26] which is why newsprint and other mechanical paper yellows with age. Paper made from bleached kraft or sulfite pulps does not contain significant amounts of lignin and is therefore better suited for books, documents and other applications where whiteness of the paper is essential.

    Paper made from wood pulp is not necessarily less durable than a rag paper. The aging behaviour of a paper is determined by its manufacture, not the original source of the fibres.[27] Furthermore, tests sponsored by the Library of Congress prove that all paper is at risk of acid decay, because cellulose itself produces formic, acetic, lactic and oxalic acids.[28]

    Mechanical pulping yields almost a tonne of pulp per tonne of dry wood used, which is why mechanical pulps are sometimes referred to as “high yield” pulps. With almost twice the yield as chemical pulping, mechanical pulps is often cheaper. Mass-market paperback books and newspapers tend to use mechanical papers. Book publishers tend to use acid-free paper, made from fully bleached chemical pulps for hardback and trade paperback books.

    Environmental impact

    Main articles: Environmental impact of paper and Deforestation

    The production and use of paper has a number of adverse effects on the environment.

    Worldwide consumption of paper has risen by 400% in the past 40 years[clarification needed] leading to increase in deforestation, with 35% of harvested trees being used for paper manufacture. Most paper companies also plant trees to help regrow forests. Logging of old growth forests accounts for less than 10% of wood pulp,[29] but is one of the most controversial issues.

    Paper waste accounts for up to 40% of total waste produced in the United States each year, which adds up to 71.6 million tons of paper waste per year in the United States alone.[30] The average office worker in the US prints 31 pages every day.[31] Americans also use in the order of 16 billion paper cups per year.

    Conventional bleaching of wood pulp using elemental chlorine produces and releases into the environment large amounts of chlorinated organic compounds, including chlorinated dioxins.[32] Dioxins are recognized as a persistent environmental pollutant, regulated internationally by the Stockholm Convention on Persistent Organic Pollutants. Dioxins are highly toxic, and health effects on humans include reproductive, developmental, immune and hormonal problems. They are known to be carcinogenic. Over 90% of human exposure is through food, primarily meat, dairy, fish and shellfish, as dioxins accumulate in the food chain in the fatty tissue of animals.[33]

    The paper pulp and print industries emitted together about 1% of world greenhouse-gas emissions in 2010[34] and about 0.9% in 2012.[35]

    Current production and use

    In the 2022−2024 edition of the annual “Pulp and paper capacites survey”, the Food and Agriculture Organization of the United Nations (FAO) reports that Asia has superseded North America as the top pulp- and paper-producing continent.[36]

    FAO figures for 2021 show the production of graphic papers continuing its decline from a mid-2000s peak to hover below 100 million tonnes a year. By contrast, the production of other papers and paperboard – which includes cardboard and sanitary products – has continued to soar, exceeding 320 million tonnes.[36]

    FAO has documented the expanding production of cardboard in paper and paperboard, which has been increasing in response to the spread of e-commerce since the 2010s.[36] Data from FAO suggest that it has been even further boosted by COVID-19-related lockdowns.[37]

    Future

    Some manufacturers have started using a new, significantly more environmentally friendly alternative to expanded plastic packaging. Made out of paper, and known commercially as PaperFoam, the new packaging has mechanical properties very similar to those of some expanded plastic packaging, but is biodegradable and can also be recycled with ordinary paper.[38]

    With increasing environmental concerns about synthetic coatings (such as PFOA) and the higher prices of hydrocarbon based petrochemicals, there is a focus on zein (corn protein) as a coating for paper in high grease applications such as popcorn bags.[39]

    Also, synthetics such as Tyvek and Teslin have been introduced as printing media as a more durable material than paper.