Foundations in Graphic Communications: Checking Color Proofs

New York City College Of Technology
Advertising Design & Graphic Arts: NYCCT

The Course At A Glance

 


Foundations in Graphic Communications
Patrick Henry     (p) 718.847.9430     (c) 917.647.0590     (e) PTHenry@Citytech.cuny.edu

     
  PAPER CHARACTERISTICS (II)  
     
 

CALENDERING (note the spelling) is a step in the papermaking process that imparts a smooth surface to the paper. It's done by running the paper through a stack of calendering rolls--metal cylinders that compress the fibers and reduce the bulk of the paper. "Supercalendering" produces an ultra-smooth, ultra- thin surfaced paper that can be used to print skinny books that have a lot of pages. The trade-offs are loss of opacity and decreased durability.

BASIS WEIGHT is the weight in pounds of a ream (500 sheets) in the basic size for that grade. Example: Basis 70 means that a 500-sheet stack of 25x38" book paper weighs 70 pounds. The basic size is not the same for all grades--each category has a size used to compute its basis weights.

The basic size for text, coated, and uncoated papers--in other words, for the papers most widely used in publishing--is 25x38". Understanding basis weight is important because mills and paper merchants sell paper by the pound, not by the number of sheets or the length of the web.

CALIPER is the measurement of a paper's thickness, expressed as a point size in thousands of an inch. One point equals 1/1000 of an inch. A 7pt. stock is .007" thick. (A caliper "point" is not the same as a typeface "point," which is 1/72 of an inch--about 14 times as large.) The smaller the caliper, the more pages per inch (ppi), and vice versa.

Caliper is not related to basis weight. Two papers of the same basis weight may be of different thicknesses. That is why we use the term:

BULK to refer to a paper's thickness relative to its basis weight. For example, an uncoated paper might be said to "bulk" higher than coated paper.

 
     
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