Paper: Definition, History, Characteristics, & Applications

Paper is an incredibly interesting and versatile material. It is a material that is deeply tied to human history, as it has been the primary means of recording that history for at least a millennium. However, paper can be made into many different variations — different colors, weights, and textures.

This article will explore some of the characteristics and applications of paper.

What Is Paper?

Paper is a sheet of pressed cellulose fibers. It is typically made by extracting the cellulose fibers from specific kinds of timber from sustainably managed forests. This sheet of cellulose fibers can be dyed, embossed, and written on. It can be produced in different thicknesses, weights, and textures. Paper is therefore an incredibly versatile material that has applications in many different aspects of our lives. This includes copy paper, toilet paper, wallpaper, and wrapping paper as only a few examples.

What Is the History of Paper?

Paper-like materials were developed in different parts of the world from different substances. Papyrus was made by the Egyptians as early as 3000 BCE, by layering slices of the papyrus reed. Tapa was made in tropical climates by beating the bark of the mulberry tree into a thin sheet. Parchment was made in Greece around the second century BCE by treating the skins of animals with lime.

However, the first proper paper made from pulped plant fibers was made in China in approximately 200 BCE. Materials like hemp, mulberry bark, and bamboo were soaked for more than a month and then beaten into a pulp. The pulp was then spread out thinly on a loosely woven screen, allowing the excess liquid to drain out. The pulp was left to dry until the paper could be peeled off of the screen.

This approach to papermaking progressed to Korea and Japan by 600 CE, and then west to Samarkand in Uzbekistan by about 800 CE. Samarkand, especially, was known for its high-quality paper. From there, papermaking spread throughout the Islamic world. The technology steadily improved and continued to spread globally, until the industrial revolution in the 1800s brought about the means for mass production of paper products.

What Is Paper Made Of?

Paper is made of plant fibers — specifically, cellulose fibers. It is made by gathering natural plant materials (lignocellulosic biomass) and treating them both mechanically and chemically. This not only separates the cellulose fibers but can also prepare them to influence the properties of the final paper product. The fibers can be long or short and are commonly bleached. The cellulose fibers knit with each other, forming a sheet of paper.

How Is Paper Made?

The modern papermaking process uses wood from selected tree species cut from managed forests as raw material. These may be either hardwoods or softwoods, depending on the application. Each species of tree will result in fibers with different characteristics. In the forest, the trees are felled and cut into logs. They are then transported to the paper mill. At the mill, the logs are debarked before being chipped. The wood chips are then chemically treated to remove the lignin from the cellulose, resulting in a cellulose pulp. The pulp is typically bleached to make white paper.

The pulp is then fed into a paper-making production line. This is a large series of machines made up of many processes that happen sequentially. The pulp is applied onto a wire screen as a thin sheet, and liquid is pressed out of it. The continuous paper sheet progresses through a series of rollers, becoming thinner and dryer. The final few rollers are heated to evaporate moisture from the paper sheet. Finally, a finishing section smooths the paper and can apply a coating to the surface of the paper according to its intended purpose.

What Are the Different Characteristics of Paper?

Paper has several characteristics that contribute to its versatility as a material. Each of the characteristics explained below adds to the available applications of paper:

1. Flexibility

Paper can be easily deformed and made to conform to objects. This is exhibited when wrapping a gift — the wrapping paper takes on the shape of the item that it covers. A large part of this flexibility is because paper is typically produced in thin sheets, and it does not take much force at all to bend these thin sheets. More than this, the knitting of the fibers of the paper means that it maintains its integrity when deformed, rather than being brittle. Paper’s flexibility allows it to be manipulated without specialized tools — just one’s hands are usually enough.

2. Durability

Although paper is relatively easy to tear or damage intentionally, the reality is that it is very durable when treated with reasonable care. Paper in a book, stored correctly in a library, has been shown to endure for more than 1000 years! Paper is an archiving material, used to keep information for the long term. It is necessary to store paper away from moisture and pests like insects and mice. Variations of paper, such as acid-free and archival paper, are specifically manufactured with durability in mind to preserve printed records.

3. Absorbency

Paper products absorb water (and most other liquids) easily. This can be a disadvantage in some applications, but it is a key feature for others. Paper towels are very common in domestic kitchens because of their absorbency. Toilet paper is also highly absorbent, allowing the paper to be easily flushed via waterborne sewerage. Paper’s absorbency is due to water clinging to the cellulose fibers of the paper.

4. Opacity

Paper is an opaque material, which means that it blocks light and is not transparent. This property of paper is used in products such as wallpaper, where coverage of the wall underneath is required. Thin sheets of paper do allow some light through, so, for opacity, thicker sheets are generally required. In art and some books, thicker opaque sheets are used to ensure that drawn or printed lines from other pages or the other side of the page do not show through.

5. Recyclability

Paper is easily recyclable, and relatively cheap to recycle as well. By soaking used paper, the cellulose fibers can be returned to a solution, and the papermaking process can essentially be carried out once more. The recovered cellulose fibers are placed on a screen, and the water is squeezed out of the sheet. Due to the fibers being reused rather than virgin, typically lower quality paper is made from recycled material, but there are still many applications for this, such as cardboard boxes and cartons for food and beverage packaging.

6. Composition Variability

Paper does have variability in its composition. This is primarily a function of the timber used to produce the paper, broadly split into hardwoods or softwoods. Typically softwoods have longer and thicker fibers, leading to stronger products than hardwoods, which generally have shorter and thinner fibers. Softwoods also tend to have more lignin and extractives than hardwoods. The specific chemicals used to make the paper also affect its final composition. This variability allows further variants of paper to be produced, such as acid-free paper or manila paper.

7. Texture and Weight Variation

Paper can be manufactured to various weight specifications, typically reflected in the GSM (grams per square meter) or lbs designation. The density and thickness of the paper are selected to match the application, such as thin book pages or more durable cardstock (cover paper).

8. Smooth or Textured Surface

Paper can be manufactured with a broad range of textures. This adds variety and creativity in areas such as: greeting cards, invitations, and other decorative stationery. Standard copy paper is generally considered smooth, but many decorative paper products can be rough, glossy, or embossed with repeated patterns.

What is Paper Used For?

Paper has many different uses (as there are many variations of paper products), but the most fundamental use of paper is to make records. Paper is used for the pages of books, and books are used to store knowledge. Historically, this was done by hand, capturing thoughts, events, and laws through handwriting the words onto paper. Since the invention of the printing press in the 1440s, paper has been used for printing. However, as the current digital age continues, this has become less essential, as records are increasingly being stored digitally. Paper’s uses continue to diversify. One example of this is the current expansion into sustainable packaging solutions.

What Are the Different Examples of Paper?

Various examples of paper exist all around us in daily life. At home, we use paper towels in the kitchen and toilet paper in the bathroom. This type of paper is thin, flexible, and particularly water-absorbent. There may be wallpaper on our walls — this paper must be opaque, and have varied finishes, coatings, and embossings. At work, copy paper is still used extensively for hard copies of documents and reports - this paper is bleached white, is optimized for cost, and holds ink well. Greeting cards are printed on thicker, higher-quality paper, which has a premium feel and is often embellished with inks, embossings, and punched patterns. There are many different examples of different varieties of paper in our daily lives. 

What Are the Different Types of Paper?

There are many different types of paper, varying in raw material (such as recycled paper, virgin hardwood, or softwood), thickness, and finish. The most common, day-to-day paper is copy paper — the standard pieces of paper that are used to print documents. These are white, are a standard, intermediate thickness, and are cut to standardized sizes. Thicker paper is generally called cardstock, but there are specific types of cardstock, such as that used for greeting cards or crafts, and the sort used for in-store advertising displays. There are also many types of thinner paper, such as: tissue paper for gift packaging, newsprint paper for newspapers, and tracing paper. Papers can also be coated or dyed to give different surface finishes, and therefore different end uses.

What Is the Advantage of Using Paper?

The primary advantage of using paper is its sustainability. It is a sustainable material for several reasons: it is biodegradable, easily recyclable, and has a very low carbon footprint. Paper is a renewable resource, especially when made from managed, sustainable forests. The trees, while waiting to be turned into paper, are also a carbon sequestration mechanism, capturing atmospheric carbon. Once paper is produced, it is easily recycled, which further limits processing costs and impacts from virgin paper manufacturing. Even if paper is not recycled, but rather disposed of, it is biodegradable. It therefore has a much smaller impact on the environment than plastic materials. All of these factors contribute to paper’s sustainability and therefore have raised the value of paper packaging products in recent years.

It should be noted that paper manufacturing is not without environmental concerns, particularly due to high water and chemical usage. However, paper is still considered a more sustainable material than plastic and metal alternatives for the reasons above.

What Is the Disadvantage of Using Paper?

The main disadvantage of using paper is its poor durability. Paper is not very strong, and therefore paper packaging has limited structural integrity and is easily damaged by impacts. Further, it is vulnerable to moisture and is easily damaged or destroyed by absorbing water. This makes it unsuitable for use with moist materials unless an additional waterproof coating is applied to the paper product.

Is Paper a Vital Material for Embossing?

Yes, paper is a vital material for embossing. Paper is a highly versatile material, and it can be embossed to provide several different textures and visual effects. These embossed effects can be used selectively in advertising and printed media to draw interest, convey further information, or highlight an aspect of the printed media. The finish applied to a paper product through embossing is another tool that can be used in product design.

What Are the Different Applications of Paper in Different Industries?

Paper has a large number of applications in multiple industries. Some of these are explained below:

1. Packaging: Paper packaging materials have exploded in popularity due to their better sustainability compared to plastic materials. These packaging materials are used for: food, electronics, and other small items.
2. Records: Paper has been the key means of keeping records for the last millennium. Although record-keeping is shifting heavily to digital media in the 21st century, there are still many applications that use paper for keeping records in hard copy. These can include: logbooks, drawing paper, receipt slips, and anything printed.
3. Decoration: Paper is a versatile material for decoration. It is thin and relatively light and can be dyed or printed in many different colors. Common types of paper that exist for aesthetic reasons include: wallpaper, wrapping paper, and tissue paper.
4. Filtering: Filter paper is used widely, from chemistry laboratories to coffee houses. Filter paper can be made to have a well-controlled pore size while still being relatively cheap. It is therefore an important consumable in many industrial activities.

Can Paper Be Used in 3D Printing?

Yes, paper can be used in 3D printing! Essentially, layers of paper (laminations) are glued together, with each layer being cut in the desired shape for that layer. Colors can even be printed onto each layer of paper, as with a traditional 2D printer. The completed object is then a series of sheets of paper glued together, making a 3D shape, but with the added element of a full range of possible colors on the surface. 

There are two key processes for 3D printing with paper: laminated object manufacturing (LOM) and selective deposition lamination (SDL). The basic process for each is similar (as described above), but SDL allows more intricate constructions and uses less adhesive. In SDL, the glue is only applied to the areas that form the completed model, making it easier to remove the support material as unglued sheets around the model.

To learn more, see our full guide on How 3D Printers Work.

What 3D-Printed Products Can Be Made Using Paper?

Paper 3D printing is particularly useful for creating models with a wide range of colors, as the CMYK ink system can be applied to get a huge range of colors onto the model surface. Images can therefore be printed together with the model, to provide a more aesthetic and visually accurate model. It is therefore useful for items such as: architectural models, educational models, geospatial contour maps, and marketing items.

To learn more, see our full guide on Products to Print.

Summary

This article presented paper, explained it, and discussed its history and characteristics. To learn more about paper, contact a Xometry representative.

Xometry provides a wide range of manufacturing capabilities and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.

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