In the early ‘90s I realized I didn’t know much about commercial printing paper other than the few paper stocks I was using for textbooks. I had already been in the printing and publications field since high school (managing two yearbooks), so it was time to remedy my ignorance, particularly since I had just been promoted to production manager/art director at the government education nonprofit foundation where I worked.
I started paying attention, reading, and looking at samples. Nothing helped more than looking at samples. I started to see and feel the differences in paper surfaces, paper weights, opacity. Thirty years later I feel confident and knowledgeable, but I’m still learning.
That said, you may be on a similar journey. You may be specifying a few tried and true paper stocks that have always been right for your publications. (I had been a print book designer prior to my promotion to art director/production manager, so I knew 60# white offset and 10 pt. C1S cover stock, but since I hadn’t designed promotional materials yet, the print book text papers and cover papers were really all I had needed to know about.)
Getting Started
If you’re expanding your knowledge of paper, the first thing I would suggest is that you contact your custom printing supplier and request a collection of paper sample boxes. If you have a paper merchant (or if your printer has one), all the better. She or he will know even more about paper than your printer. It also doesn’t hurt to have a 12x printer’s loupe (a high-power magnifier) and a paper micrometer, which will help you determine the thickness (caliper) of the paper samples.
It also helps to download from the internet a paper comparison chart. Since different paper categories have different “basic sizes” (the size at which a ream of paper is weighed to determine the “basis weight”), a paper comparison chart helps you see how the actual thicknesses of offset cover stock, offset text stock, bristol board, tag board, bond, index, etc., compare to one another.
This handful of paper tools will make your printing paper education easier and more enjoyable. And in fact, if your printer offers to set up a paper mill tour for you, jump at the chance. The Fourdrinier machine is huge, like a football field in length, and you can watch paper morphing from a liquid mixture to the dry, flat surface you’re used to printing on.
Random Terms
For now, here are some random paper terms in no specific order, including a number of kinds of paper you might not yet know about.
Kraft Paper
Large brown envelopes are made of kraft paper. This is a strong stock that is used for wrapping paper as well. The paper fibers are very durable; hence, the paper is good for protecting anything going through the mail. Kraft paper is made from wood chips broken down into fiber by sodium sulphate and sodium sulfide (or other, similar chemicals). That is, the wood is made into a liquid pulp via a chemical decomposition process. For uses other than wrapping paper and envelopes, kraft paper can be bleached to whiten the press sheet for commercial printing.
Cast-Coated Paper
Cast-coated paper is to custom printing stock what patent leather is to shoes. Nothing has a glossier surface. This can be particularly good for an invitation or perhaps a print book cover. Cast-coated paper provides a mirror-sharp finish that has a high-tech feel. In the papermaking process, the wet paper coating is smoothed to a gloss sheen through contact with a stack of polished metal rollers (calender rollers).
Freesheet vs. Groundwood
The term freesheet refers to “lignin-free” (a contaminant in paper pulp that breaks down the fibers over time, reducing its longevity) and also free of mechanical pulp or groundwood. If you’re producing a parts catalog for a mechanic, this isn’t a problem. However, if you’re producing paper for accounting ledger books, you want the paper to last a long time. The opposite of a freesheet is a groundwood paper. Groundwood is mechanically pulped (the wood chips are physically ground up rather than chemically dissolved). Newsprint is a groundwood sheet.
Archival Paper (Acidic vs. Basic)
The aforementioned characteristics of a groundwood vs. freesheet paper directly pertain to the archival quality of a paper stock. Archival paper is more alkaline; cheaper paper like newsprint is more acidic. I have books from the 1800s with paper that is still pristine. In contrast, I also have paperbacks from the 1970s with paper that has yellowed and become brittle. This is the effect of paper acidity.
Deckled-Edge Paper
It is possible to give a press sheet (while it goes through the papermaking machine) the appearance of handmade paper stock, including the feathered edge called deckling. In this case either a jet of air or a stream of water is sprayed against the paper during the manufacturing process, giving a feathered-edge look to the paper.
Index Bristol and Tag Board
Index bristol is a rugged paper that can tolerate erasing. It is good for business forms and mailing. It is also good for the fine arts (drawing, for instance). Bristol is a thick stock. For example, when I was an art director, I used to specify 67# vellum bristol when I needed a reply card for a promotional mailer. Clients could write easily on the uncoated surface, which accepted ballpoint pen ink, and the 67# thickness was exactly what the US Post Office required for small business reply cards. As I recall, it was 7pt thick. A similar paper, tag board is used for tags (garment tags in clothing stores, for instance). Tag board may include such substances as rope and jute to increase its strength. Tag board has a smooth surface you can write on, but it is not archival.
Parchment
Initially (as in the 2nd Century, BC) parchment was made from animal skins: sheep, goats, and calves. Now it is made from cellulose fibers soaked in sulfuric acid. The acid gives the paper a mottled look. Parchment paper has a very hard surface that keeps water, dirt, and oil from soaking in.
Parchment Tracing Paper
Similar in name to parchment paper, this is a thin, hard, transparent sheet that is good for tracing.
Vellum Paper
Vellum paper is made to simulate parchment that has been made from calfskin. A transparent vellum sheet in the beginning of a book before the title page will just slightly obscure the title page (a bit of a tease). It’s also good for tracing, and it comes in both cream and natural (clear) color. Vellum paper is different from “vellum finish” paper, which refers to a somewhat rough and absorbent (and uncoated) paper surface.
Rag Paper
This is paper made from cotton fibers rather than wood fibers (literally cloth rag cuttings). Rag paper may also include linen fibers. Papermaking companies use bleach and other cleaning agents to brighten the stock, which is quite good for specialty products such as fine writing paper. Rag paper absorbs ink especially well and has none of the impurities that make wood-based paper acidic. (Therefore rag paper is great for its archival properties.)
Linen Paper
This refers not to the content of the paper pulp but to the finish applied to the paper by a roller during the papermaking process. Linen paper has a characteristic woven look that mimics the cross-weave of linen fabric.
Cardboard
I know of at least three kinds of paper referred to as cardboard. The first is offset cover stock, which is thick paper corresponding to a compatible text weight. You might specify a 100# cover sheet and an 80# or 100# text sheet for the cover and text of an annual report. The text sheet is weighed at a basic size of 25” x 38”, while the cover stock is weighed at a basic size of 20” x 26”; hence, they both have the same weight for 500 sheets—a ream–even though one is much thicker than the other. Cover paper is heavy; therefore, some people call it cardboard.
The second reference is to chipboard, which is what shoeboxes and the cards at the back of pads of paper are made of. It is of low density and is made from unused waste. High-class shoeboxes often have additional paper covering the chipboard.
The final option for cardboard is corrugated board, which is made of fluted paper that curves back and forth in an “S” pattern. This fluting is sandwiched between two liners, front and back, which may be printed before lamination to the fluting. Now many printers use inkjet commercial printing technology to image directly on converted corrugated board (i.e., to print directly on the outer liner). Corrugated board is light but incredibly strong. When I was growing up, liquor stores boxed their bottled spirits in this kind of cardboard cartons. Chipboard boxes would cave in under that much weight.
I noted this before, but I would think that tag board, bristol board, and index stock would also fit the bill for cardboard.
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on Monday, May 23rd, 2022 at 12:36 am and is filed under Paper and finishing.
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