At the same time that you're checking out the printing terrain, you should also be learning more about paper. After all, it's impossible to accurately solicit printing quotes or create print order specifications without knowing the paper your project will be printed on. Paper differs in terms of colour, texture and weight. Other important terms include opacity, ink-holding power, and brightness.
- Colour refers to tint. Remember that the background of your pages influences how ink colours appear. Book stores specializing in graphic arts often stock books showing how various ink colours look when printed on different coloured papers.
- Surface texture involves the content of your publication and the image you want to project. Photographs reproduce best on smooth finished papers, but the trade-off is that coated (or glossy) paper may make serif text difficult to read. Strive for a balance between photo quality and feel (how the paper feels in your hand). Antique and vellum finishes are noticeably rough, while satin and polished stocks are very smooth.
- Weight is measured in terms of 500 sheets. The size of the paper being weighed, however, differs depending on whether the paper is designed to be used for the insides of a book (text stock) or the cover of a book (cover stock).
- Opacity refers to the degree to which ink printed on one side shows through to the other side. Opacity is a function of the thickness of the paper, how tight the fibres are woven, the colour of paper and whether or not it is coated.
- Colour, texture, and weight variations are not always available in all sizes. You may find that the perfect paper is not available in a size that permits cost-effective printing.
Paper may be defined in terms of its use. Each grade serves a purpose, usually suggested by its grade name. Some of the most common classifications of printing papers are bond, coated, text, cover, book, offset, index, label, tag and newsprint. The size shown in parenthesis is one of the basic sizes for that grade. Each grade will have several levels of quality, colour, texture and weight.
Bond (17 x 22) papers are commonly used for letters and business forms. They have surfaces which accept ink readily from a pen or typewriter and can be easily erased. Most letterhead and business forms are a standard 81/2" x 11" size.
Writing (221/2 x 35) papers are noted for their interesting textures and attractive colours. They are lighter weight than text, but higher quality than bond. They are used for most stationery packages as they come with matching envelopes, as well they can be used for brochures and booklets.
Coated (25 x 38) papers are used when high printing quality is desired because of its greater surface smoothness and uniform ink receptivity. There are many kinds: cast coated, gloss coated, dull coated, coated one and two sides, etc.
Text (25 x 38) papers are noted for their interesting textures and attractive colours. They enjoy frequent use for announcements, booklets and brochures.
Offset (25 x 38) papers are used for trade and textbooks as well as general printing. They are less expensive than text papers, and are made in antique or smooth finishes. Book papers have a wider range of weights and bulk than text papers so it is possible to secure almost any desired bulking.
In response to growing demand for recycled paper products, paper recycling is increasing worldwide. Recycled newsprint has been used for years, but recycled papers for business and commercial printing only came into moderate use during the late 1980s. Driven by concerns over landfill closures and the need to reduce municipal solid waste, shipments of recycled fiber content printing and writing grades are increasing rapidly.
While a small portion of these grades have performance or appearance characteristics not equal to their virgin counterparts, the vast majority exhibit no noticeable differences.
Grain is an important factor for both printing and binding. It refers to the position of the fibers. During papermaking most fibers are oriented with their length parallel to that of the paper machine (machine direction) and their width running across the machine (cross direction).
Grain affects paper in the following ways, and these facts need to be considered in the proper use of paper (1) paper folds smoothly with the grain direction and roughens or cracks when folding cross-grain. (2) paper is stiffer in the grain direction and (3) paper expands or contracts more in the cross direction when exposed to moisture changes.
Tear and fold tests: Paper tears straighter with grain
Paper folds more easily with grain
In books and catalogues, grain direction should be parallel with the binding edge. If it is perpendicular with the binding edge, the pages turn less easily and do not lie flat. Paper for sheetfed offset is usually grain long. Moisture changes affect the shorter dimension and register problems are reduced.
Finish is a complex paper property related to its smoothness. The usual finishes of uncoated book papers are, in order of increasing smoothness: antique, eggshell and vellum. Coating, of course, further improves the finish and smoothness.
Some finishes are embossed on the paper after it leaves the machine. These are produced by a rotary embosser, with the paper passing through it dry and under pressure. Commonly used embossing patterns are linen, laid and felt finish.