Help Understanding Paper Weights and Finishes
Paper weights and types can be very confusing. What follows is a general guide to help understand the sizes and terms and to associate them with items that you are familiar with. There are two basic systems in use: the U.S. system (traditional English system), which sizes the weight in pounds, and the Metric system, which sizes the weight in grams / meter squared (g/m²), or more commonly referred to as grams per square meter (gsm).
The U.S. System
The U.S. system is more difficult to understand because the same number in pounds can be used for the thicker card stock or the thinner text papers. In the U.S. system, a paper's weight is the weight, measured in pounds, of one ream. But every type of paper has its own size of ream! The metric system however is standard across all weights of papers. It measures a fixed size--one square meter.
The Metric System
Grams per square meter (gsm) gives a much better idea as to the actual thickness of a paper. As a general rule, anything 10-35 gsm is of tissue consistency; 35-70 gsm is lighter textweight, 70-100 gsm is medium textweight, 100-120 gsm is heavy textweight/light cardstock, 120-150 gsm is regular cardstock weight, 150-200 gsm is heavy cardstock, and greater than 200 gsm is super heavy cardstock.
For an example, lets compare two papers--a 65 lb Cover (a very common cardstock) and an 80 lb Text. Using the U.S. system, you might think that the 80 lb Text is a thicker paper--after all, it weighs more, right? But a Text weight paper has a 'feel' like a letterhead or stationary paper. Cover weight (cardstock) will have a 'feel' like a business card or post card. And if you had a sample of each in your hand, you would discover that there is a difference in thickness--the 65 lb Cover would be thicker and stiffer than the 80 lb Text. Using the Metric system however, these two papers would actually be 175 gsm (65 lb Cover) and 120 gsm (80 lb Text). The paragraph below gives approximate gsm for different common weights of paper; the actual gsm of a paper type depends upon the manufacturer.
WOVE, SMOOTH, BOND, VELLUM - Reasonably smooth to the touch with subtle differences
Paper with a WOVE finish is one of the most common papers used for general printing. Wove finish is a standard smooth even finish. SMOOTH finish is a finish that has been made very smooth and level from the paper passing through sets of rollers during the papermaking process. BOND paper is a relatively high-grade paper stock generally used for letters, business forms, and copying. Some types of bond paper may have a rag content ranging from 25 percent to 100 percent. VELLUM is a very common finish for all purpose papers. It will appear smooth to the untrained eye, although the paper has a subtle roughness (tooth) which separates it from smooth.
EMBOSSED, LINEN, LAID, FELT - Textured visually and to the touch
EMBOSSED finish is a molded appearance onto the paper sheet. The appearance of the emboss may cause the paper to be defined by the way it looks, such as the following paper finishes (linen, laid, felt, etc.). LINEN is a paper finish that resembles linen cloth which is usually produced after the papermaking process as an offline embossing process. LAID is a finish has the appearance of fine lines running the length of the paper. It is produced during the papermaking process with a special roller that creates the pattern in the wet paper. And FELT resembles felt.
PARCHMENT, COCKLE - Antique appearance
PARCHMENT is a paper finish that has an old or antique appearance. COCKLE is a finish that simulates characteristics of hand made paper. The effect is obtained by air drying the paper under minimum tension.
METALLIC, COATED, CAST COATED - Commonly achieved by a coating process
METALLIC Paper is coated with a thin film containing metal or a thin film of plastic whose color and gloss simulate metal. COATED is paper that has had a coating applied to give the sheet a better appearance. The coating can be applied to one side or both sides. CAST COATED is paper or board with a coating that is allowed to harden while in contact a highly polished chrome surface. This results in an exceptionally glossy coated finish, usually only on one side.
TRANSLUCENT - See through paper
TRANSLUCENT is a thin paper that does not have the same clarity as acetate, but can be used as an overlay allowing any content placed immediately beneath it to be viewed through it with some lack of clarity (semi-transparent). Translucent is not technically a finish, and 'vellum' and 'translucent' are different. Translucent paper may have a vellum finish, although so do many opaque (can't see through) papers. This is why you may see it called 'Translucent Vellum', because vellum is the paper's finish.