We know that the world of paper seems to use its own language. That’s why we’re committed to helping you understand the complex nomenclature and simplify the specifying process – to ensure you have the right paper for the job, every time. There are basic criteria necessary for specifying paper: brightness, whiteness, opacity, surface and basis weight or calliper if your paper is being used for direct mail purposes.
Brightness is reflected light. Since the inks placed on paper are transparent, it is the paper that actually acts as a light source and supplies the light to the ink. Brightness, like the wattage of a light bulb, enhances impact and creates contrast. Thus, a sheet with high brightness will make artwork and photography pop. With lower brightness, overall contrast is reduced and highlights are dulled.
Shade is the uniformity of reflected light across the full spectrum – in essence, the colour of white. Shade determines how accurately a colour image is reproduced. The “whiter” the paper, the more vibrant the highlights, reflections and contrast in the printed imagery.
Papers come in a variety of surfaces, also known as finishes. The most common coated surfaces are gloss, silk, dull and matte. Each of these surfaces provide different print qualities and overall appearance. Each has its strengths and appropriateness for a particular job. To determine the appropriate finish of the paper, we have to consider the printed piece’s desired end-result and function. For example, a gloss finish offers the ultimate in reproduction detail, while dull and matte finishes offer easier reading for large quantities of text.
Also known as “show-through,” opacity describes the amount of printed matter that is visible from the opposite side of a printed sheet. The opacity of a paper is attributable to the manufacture of the base sheet, the thickness of the sheet and chemical additives to decrease the translucence of the paper.
There are two types of opacity. “Apparent opacity” refers to the actual opacity of the unprinted paper itself. “Printed opacity” is the opacity of the printed paper. It is affected by ink holdout, and is lower than the apparent opacity of the paper. This reduced opacity is actually caused by absorption of ink. As ink is absorbed into a sheet of paper, the printed opacity of the page decreases, causing the image to show through on the back which interferes with content, detail and continuity of the image being viewed.
Basis Weight and Calliper
Most brands come in a variety of basis weights in both cover and text. Basis weight is calculated using a centuries old formula based on “parent” size or trimmed sheets of paper. Five hundred sheets (a ream) of paper cut to a specific “parent” size was used to determine if the paper was destined to be bond / writing, text / book or cover weights. For example, a cover weight paper is thicker and heavier than text paper, so the weight of 500 sheets will be heavier. Nobody weighs 500 sheets anymore but the basis weight is still calculated per ream. Paper is also manufactured to a thickness, or “calliper” or point (0,25 mm) size—this is of particular importance when the final piece must meet postal requirements, which dictate either seven point or nine point thickness be used to run through postal services machines.
Printers profile or “fingerprint” their presses with specific papers in mind, usually their “house” sheets or grades they frequently print. In fact, they often have specific performance data for the combination of paper, inks, press and pre-press techniques being used. Printers can be invaluable in helping specify a sheet.
There are several things to consider when trying to specify a paper. That is why it’s critical to look at printed samples when evaluating any paper characteristics.