Paper Characteristics

Selecting paper is a very important job for the designer, and there are a number of paper characteristics, including: weight, grade or type, color, brightness, reflectance, opacity, smoothness, and grain. For a very practical guidelinon how to order paper, see "Buying Paper" . Also, you may want to read How Paper is Made.

Paper Weight:

Caliper: Caliper is the thickness of a sheet of paper expressed in thousandth of an inch. This measurement is taken with a micro meter. Normally, paper caliper should not have more than a plus or minus 5% variance within a sheet. Usually the greater the caliper (the thicker the paper), the greater the paper weight but this depends on the density and finish of the paper. Therefore, the following chart is meant to be approximate. Every Paper.com paper shows the caliper for that particular paper.

Basis Weight: The basis weight of a paper is the weight of 500 sheets, measured in pounds, in that paper's basic sheet size. It is important to note that the "basic sheet size" is not the same for all types of paper and it is never 8 1/2 x 11. 8 1/2 x 11 is the result of cutting a Basic Sheet of Bond paper.

Equivalent Weight: While different paper types have different basic sizes, papers can still be compared by using equivalent weight. For example a 24 pound bond has the equivalent weight as 60 pound offset. (From: http://www.paper.com/chartpaperweights.html)

Paper Type (see “Paper Grades”)

Paper Color is especially important as it affects the color reproduction of lighter tints. Paper colors vary with advertising fads from cool to warm shades. Type is more easily read against a soft (yellowish) white, while process colors reproduce most accurately on neutral white paper. (PocketPal, International Paper)

Brightness affects the contrast, brilliance, snap or sparkle of the printed subject. Artificial brighteners, like florescent additives, can affect color reproduction since most are not neutral in color and have excess blue reflectance. (PocketPal, International Paper)

Reflectance:

Paper A: R=80%; G=80%; B=80%

Paper B: R=80%; G=80%; B=85%

Paper C: R=85; G=85; B=80

Paper A is the whitest; Paper B is blue-white and is the brightest; and Paper C is yellow-white and reflects the most light. The most suitable paper for color reproduction is Paper A as it is neutral and all colors printed on it will be in color and gray balance. Colors printed on paper B will appear bluish; colors printed on Paper C will appear yellowish or reddish. (PocketPal, International Paper)

Opacity: Relates to the show-through of the printed page from the opposite side of the sheet or the sheet under it. Higher opacity is achieved by increasing the mineral filler content or caliper of the paper. (PocketPal, International Paper)

Smoothness is a very important property for letterpress and gravure but has little effect on offset. Smooth surfaces have irregularities of the order of 0.0005” to 0.010” apart. They cannot be seen to the naked eye, but can be detected by a magnifying glass and low angle illumination. As smoothness decreases, solids and halftones get sandy and rough in appearance but type is hardly affected. (PocketPal, International Paper)

Paper Gloss is the shiny and lustrous appearance of the aper due to the addition of coating and calendering in manufacture. (PocketPal, International Paper)

Printed gloss is related to ink gloss and holdout as well as paper gloss. (PocketPal, International Paper)

Refractiveness relates to light absorption in the surface of the paper, causing halftones to appear darker than they should. (PocketPal, International Paper)

Grain: The direction in which most fibers lay in a finished sheet of paper is referred to as grain. Fibers flow parallel to the direction in which the paper travels on the paper machine during manufacture.

Grain can influence other characteristics of paper….. Heavier-weight paper, like cover and bristol, may fold without scoring when folded parallel to the grain; scoring will be necessary, however, when folding across the grain. A sheet of paper will generally offer greater resistance to being torn against its grain.

There are two basic classifications of grain: grain long and grain short. Grain long indicates that the paper grain is parallel to the longest measurements of the sheet. The fibers are aligned parallel to the length of the sheet. By contrast, grain short indicates that the paper grain runs at right angles to the longest dimension of the sheet. Fiber alignment in paper with short grain parallels the sheet's shortest. (From “The Basics of Buying Paper”)

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Department of Communication, Seton Hall University