Pulp Fundamentals (1,669 words)
Often, you use a heavier paper when you want give the impression of worth. A light flimsy paper might convey that your product is flimsy. Heavy paper will give an impression of strength and stability. If you are going to put a lot into an envelope you might also want to use a 28-pound wove instead of a more common 24-pound wove.
Don't forget, you also pay postage by weight. Generally, the heavier the mail piece, the more you pay. If you want to mail first class, you must be particularly careful because one ounce adds up very quickly. When your weight is over an ounce your postage goes up significantly. Standard mail allows you a little over three ounces before you have to pay extra.
International mail all goes by weight so you want to generally use as light a paper as you can.
You buy paper by weight. The heavier it is, the more you pay. One way to reduce your paper costs is to "lighten up."
Weight will also add opacity to your paper.
Opacity is the measure of how much you can read on the back of a piece of paper without having to turn it over. It is very important on letters as poor opacity can really detract from the look and readability of your letter. Brochures generally are printed on a little heavier paper so it doesn't seem to be as much of an issue, but it can be.
When weight is a consideration (first class or foreign mailings) you can use an Opaque sheet. These are made with extra titanium and a lighter weight will have the opacity of a heavier "normal" sheet. A 40-pound opaque can work great for letters. You pay more per pound for these papers but you need fewer pounds.