Text 4 Types of paper

Newsprint Newsprint is a machine finished paper, made mostly from groundwood pulp and used for printing newspapers and cheap handbills. It discolours readily when it is exposed to light, due to the impurities (lignin) contained in and around the fibre.

Mechanical papers contain a large proportion of mechanical wood pulp, but also some chemical pulp to increase strength. The mechanical element may be bleached. Paper can be produced with a smooth surface by super calendering (SC), machine finishing ( MF), or machine glazing (MG).

Woodfree paper is still made from wood pulp, but it is produced by the chemical, rather than the mechanical process. Strong sheets with good whiteness are produced for use as general printing and writing papers, continuous stationery, copying papers and magazine papers.

Cartridge papers are tough, hard sized papers that were originally used in the production of cartridges. The quality has been extended to most rough-surfaced heavy papers.

Board is normally used for covers to catalogues and paperback books and for the production of cartons. It may be uncoated or supplied coated on one or two sides. Board weights normally start at 160gsm. The thicker boards may be made by laminating two or more plys of material together.

Antique normally relates to a bulky paper with a naturally rough finish (antique wove), similar to that of an uncalendered handmade paper, It is mainly used in the production of books.This paper is not suitable for halftones or line work with large solid areas of colour or fine detail.

Coated papers Art paper is coated on both sides with china clay (the best clay is British) and calendered to give a very high smoothness and gloss, It is used for the printing of halftones and colour and high-quality magazines and promotional material.

Matt art is produced in a simlar way to art paper by coating with china clay, but the calendering process is only used to consolidate the surface rather than to produce a high gloss. As a result, the surface has a matt appearance but still gives good reproduction of halftone colour prints without gloss interfering with print defini­tion.

Blade coated cartridge paper is midway between being an uncoated and a matt art paper. It has a lighter coating than art or matt art, but reproduces halftones well. It is used for some magazine work and illustrated books like this one .

Chromo is coated on only one side and is used for posters, proofing work, printing of book jackets and labels.

Cast coated papers are characterized by exceptionally high gloss. Cast coated papers are used in the production of prestigious cartons or covers for presentation material.

Plastic papers are made completely from plastic or with a plastic coating over a base paper. Although expensive, these products are ideal for the production of some maps, workshop manuals and books for young children. They are very tough and washable.

Carbonless copying papers are produced by employing a coating of micro capsules that rupture under the pressure of a stylus or printer key, releasing a solution of colourless dye. This transfers to the reactive surface on the sheet below where the dye is converted to its coloured form.

Technical papers Many types of highly specialized papers are manufactured either through modification to the basic paper making process, blend of pulps, use of additives or after processing. These include papers for currency, photography, filters, electrical cable winding, decorative laminates, security applications, and postage stamps.

Exercises:

I. Read the sentences and say if they are true or false. If they are false, correct them.

II. Find the equivalents of the following terms:

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i)

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k)

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m)

n)

o)

p)

q)

r)

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III. Fill the gaps using the following words:

IV. Compare different

V. Write a short summary of the text.