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Paper glossary

Absorbency. The extent to which wet ink is absorbed into the paper.

Basic Size. The customary sheet size used to establish the basis weight of a ream (500 sheets) of a given paper. Standard basic sizes vary by paper.

Basis Weight Measurement. Pounds of a ream (500 sheets) of uncut paper.

Brightness. A measure of the amount of light diffusely reflected to the eye from the paper surface. There are five standard grades of brightness.

Calendering. Passing paper between polished metal and resilient rolls at high pressure to increase gloss and smoothness.

Cast-Coated Paper. High gloss papers on which a thick layer of coating is applied over the specially prepared base stock. The coated surface is then pressed tightly against a heated, highly-polished, chrome-plated drum and dried. In this way, the gloss of the drum is cast into the paper's surface.

Coated Paper. Treated with a layer of pigment designed to improve the paper's finish, smoothness and printability (ink holdout).

Dull-Coated Paper. A paper coating similar to a dull varnish in that it has a micro-textured surface that scatters the light reflecting off of it. The diffuse reflection results in a low-gloss surface. Also called satin, silk and velvet.

Finish. A description of the kind of surface of a paper sheet, including gloss or matte and any special patterns placed in the paper, such as wove or linen. Matte paper reflects light less uniformly, making it easier to read lots of text (think books). Gloss finishes produce better holdout and contrast, making images look more vivid and increasing the brightness of the paper. Finishes include dull, matte, and glossy.

Grain. With sheet paper, the grain direction is indicated by underscoring the dimension along which the grain lies, or by changing the order of the numbers. For example, a 23" by 35" sheet is grain long; grain short is indicated by 35"X23". For books and other bound work, the grain should run parallel with the binding.

Grain Long. Grain long refers to grain running along the length, or long side, of a sheet of paper. Fibers line up parallel to the long side of the paper.

Grain Short. Grain short refers to grain running along the width, or short side, of a sheet of paper. Fibers line up parallel to the short side of the paper.

Gripper Edge. The leading edge of paper that moves through a press or folding machine. No printing can take place on the outside 3/8" to 5/8" of the paper on the gripper edge, depending on the press. It is best to allocate 3/8" to 1/2" for side guides and trims and colors bars on the tail. Watch out! There may be two gripper edges if the job is run Work and Tumble!

Holdout. How well a paper holds ink on its surface instead of absorbing the ink. If a paper has poor holdout, your images will have a lot of dot gain. Newsprint, for instance, has relatively poor holdout capabilities. The more the ink soaks in, the higher the dot gain, and less crisp the printed image.

Matte Coated Paper. Paper coated with a mixture of pigments, adhesives, and additives that promote diffused reflection of light, creating surfaces with a low gloss. No calendering operations are involved.

Opacity. A lack of transparency. The higher the opacity, the lower the show-through, where you can see through a sheet to what is printed on its reverse or on the next sheet below.

Smoothness. The degree of uniform surface consistency for a given sheet. Smoothness affects how well a sheet of paper will hold ink.

Trim Size. The final size of a printed piece after all bleeds and folds have been cut off.

Uncoated Paper. A paper with no coating. Uncoated papers absorb more ink, increasing dot gain and reducing ink holdout. There are many variations in finish and surface quality.

Whiteness. The ability of a paper to equally reflect colors; a measure of the uniformity of reflection of light. If a paper reflects all colors equally, it will appear white. If it absorbs some colors more than others, than it will have a color cast.

           


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