Basic Size and Basis Weight
The basis weight refers to the weight in pounds of
500 sheets of paper when it has been cut to that paper's standard
basic size. For example the basic size for Bond paper is 17 x 22 inches.
If 500 sheets (a ream) of Bond is cut to its basic size of 17 x 22
inches and weighs 20 pounds, it is classified as 20 lb. bond. If a
17 x 22" ream of Bond paper weighed 24 pounds it would be called
24 lb. Bond, and so on. The chart below contains some common paper
types and their basic size.
17" x 22"
17" x 22"
25" x 38"
25" x 38"
20" x 26"
25-1/2" x 30-1/2"
22-1/2" x 28-1/2"
22-1/2" x 28-1/2"
24" x 36"
ISO Size Standards
The International Organization for Standardization
(ISO) has established standards for paper sizes based on the metric
system (millimeters). The standards have been grouped into three different
series of requirements: "A-series", for general printing,
"B-series", for posters, and "C-series", for envelopes,
postcards, and folders. The "A" series is the most commonly
used with sizes ranging from A0, which is the largest, down to A8.
The A-series sizes are all represented as a part
of the area of one square meter with a length to width ratio of 1.414.
The size A0 is equivalent to the area of a square meter with each
smaller size being 50% of the size of the preceding one. A1 is 50%
of the area of A0, A2 is 50% of A1, and so on. Another way to look
at it is that when an A0 sheet is cut in half, two A1 sheets are produced,
and when an A1 sheet is cut in half, two A2 sheets are produced. Some
of the sizes for the A-series are shown in the illustration below.
North American Size Standards
Although the ISO size standards are common in many
parts of the world where the metric system is the established standard
for measurement, North American sheet sizes are based on inches and
are shown in the illustration below.
Universal Web Sizes
The paper rolls shown below are the standard widths
used on web presses. The illustration also shows the standard ISO
sheet sizes and the standard North American sheet sizes that can be
obtained from each roll width.
The chart below shows the actual thickness of various
weights and grades of paper. The readings are taken with a caliper
or micrometer gauge, which measures the thickness of the paper in
thousandths of an inch.
15 lb. Bond
20 lb. Bond
24 lb. Bond
100 lb. Tag
125 lb. Tag
150 lb. Tag
28 lb. Ledger
32 lb. Ledger
36 lb. Ledger
4 Ply Railroad Board
6 Ply Railroad Board
8 Ply Railroad Board
50 lb. Regular Offset
60 lb. Regular Offset
70 lb. Regular Offset
50 lb. Smooth Offset
60 lb. Smooth Offset
70 lb. Smooth Offset
50 lb. Gloss Coated Book
60 lb. Gloss Coated Book
70 lb. Gloss Coated Book
80 lb. Gloss Coated Book
100 lb. Gloss Coated Book
120 lb. Gloss Coated Book
90 lb. Index
110 lb. Index
50 lb. Coated Cover
60 lb. Coated Cover
100 lb. Coated Cover
57 lb. Vellum Bristol
67 lb. Vellum Bristol
125 lb. Plate Finish Printing Bristol
150 lb. Plate Finish Printing Bristol
15 lb. CB Carbonless
20 lb. CB Carbonless
15 lb. CF Carbonless
20 lb. CF Carbonless
The finish refers to the surface characteristics
of the paper such as how the paper feels...is it smooth such as glossy
cover or rough with an antique finish? Does the paper have a glossy
appearance such as coated glossy papers or is it dull like bond paper.
Does the paper enhance the look of the printed piece similar to watermarked
paper or is it purely functional like newsprint? Does the paper have
a high ink absorption rate as does Vellum or poor absorption such
as on coated papers?
Finishes can be applied to paper during the manufacturing
process or produced offline. A finish such as Laid can be created
while it is being manufactured with the use of a marking roller that
forms the pattern in the paper while it is still wet. Paper finishes
provided offline are usually accomplished with steel rollers that
press the pattern into the paper. The offline finishes are known as
embossed finishes. Some common paper finishes are described below.
- Cockle - A cockle finish simulates characteristics of hand
made paper with a wavy, rippled, puckered finish. The effect is
obtained by air drying the paper under minimum tension.
- Felt - Felt is a soft texture on uncoated paper that is
created during the papermaking process with a either felt covered
roller or with a rubber roller with a felt pattern that creates
the finish. It can also be accomplished as an offline process. The
felt finish does not affect the strength of the paper.
- Gloss - A gloss finish produces a shiny and reflective
surface on one or both sides of certain coated papers. A higher
gloss is usually seen on higher quality coated papers. The gloss
finish is produced from compounds added during the paper making
- Laid - A laid finish has the appearance of translucent
lines running horizontally and vertically in the paper. It is produced
during the papermaking process with a special roller that creates
the pattern in the wet paper.
- Linen - Linen finished paper resembles linen cloth and
is usually produced after the papermaking process as an offline
- Matte - A finish on certain coated papers that is smooth
but gives a dull appearance. A matte finish, as well as other types
of coated paper, are good choices for print jobs in which high quality
- Parchment - A paper finish that has an old or antique appearance
and is the result of washing sulfuric acid over the paper and then
quickly neutralizing the acid wash. This process melts the outer
paper fibers which fill the voids in the rest of the paper. Parchment
is very durable and grease resistant.
- Smooth - A smooth finish is the result of the paper passing
through sets of rollers during the papermaking process. This process
is known as calendering.
- Vellum - A vellum finish has an eggshell appearance and
is consistent and even but not as much as a smooth finish. Vellum
is one of the most popular uncoated finishes and paper with this
finish has a high ink absorbency rate.
- Wove - An even finish in uncoated paper with a slight texture
made by a felt roller covered in woven wire.
The grain of the paper refers to the direction of
the fibers in a sheet of paper. Long grain paper refers to paper in
which the fibers run in the same direction as the longest measurement
of the paper. On rolls of paper for web presses, the grain runs along
the length of the web. Short grain paper refers to paper in which
the fibers run in the same direction as the shortest measurement of
the paper. When paper is torn, it will tear easier and straighter
when torn parallel with the grain. It will also fold easier parallel
to the grain and produce a cleaner fold than if folded across the
grain. Laser printers require long grain paper for the best results.
Short grain paper may not feed properly into a laser printer and the
heat produced by a laser printer may result in the sheets curling
as they come out of the printer.
The whiteness of paper is the measure or its ability
to reflect the colors of light equally. The more evenly a paper reflects
all colors of the spectrum, the whiter the sheet. Some papers may
reflect slightly cool colors back to our eyes and give the illusion
that the sheet is actually brighter than white paper. If white paper
has a slight warm appearance it will not appear as bright as a sheet
that reflects a cool color, however warm colors printed on a warm
sheet will appear stronger than when printed on a cool sheet. Cool
colors printed on a cool white sheet are also enhanced in the same
way. There is no such thing as a pure white sheet of paper, since
the white that we see is always influenced by the lighting of our
environment and the reflections from surrounding objects.
The grade of a paper refers to the type or category
of the paper contents which provide a level of brightness or surface
characteristics used to determine the grade level of the finished
paper stock. Grades are classified from "Premium" at the
highest level to "5" at the lowest level. Some text and
cover stocks are listed simply as A or B grades since fewer grades
of the text and cover stock are produced. A table illustrates
the grade levels of paper according to the degree of brightness.
Brightness refers to the percent of light reflected
back from a sheet of paper as measured by a light meter reading. Contrast
is reduced and highlights are not as strong when paper with a lower
brightness is used for a printed piece. The quality and brightness
of paper is organized into six categories:
88.0 to 95.0 Brightness
85.0 to 87.9 Brightness
83.0 to 84.9 Brightness
79.0 to 82.9 Brightness
73.0 to 78.9 Brightness
72.9 and below
Opacity is the measure (percent) of the amount of
light passing through a sheet of paper. Some papers have more fibers
and/or fillers and as a result are more opaque than others. Papers
containing more fibers and fillers have the ability to hold a printed
image without showing through to the backside as easily as papers
without as many fibers and fillers. Just because a paper is thicker
does not guarantee that it is more opaque than a thinner paper. Some
thinner papers may be more opaque because there are a greater number
of fibers and/or fillers in their composition.
The smoothness level is a measure of the surface
characteristics of paper. The flatter or more even the surface, the
higher the level of smoothness. With a smoother surface, the stock
can provide a fully shaped ink dot resulting in a sharper and higher
Holdout refers to the property of ink remaining on
the surface of the paper rather than soaking in. A coated glossy paper
has a high holdout rate while a paper stock such as newsprint or 20
lb. Bond has a high absorption rate or a low holdout rate.
The pH (potential for Hydrogen) measurement of paper
determines the degree of acidity and alkalinity in the stock. The
pH scale has readings of 0 to 14 with 7 being neutral. Readings below
a pH of 7.0 are acidic and above are alkaline. Each single digit actually
equals a measure of 10, so a stock measuring 4.0 pH is 20 times more
acidic than one measuring 6.0 pH. Paper can have an acid base, an
alkaline base or it can be neutral with a pH of 7. Most paper manufactured
in the 20th century was of an acid base. Acidic papers deteriorate
in a relatively short period of time, and should never be used for
printed items that are intended to last for many years. Since the
1970's, most of the paper used for book publishing and other printed
materials where permanence is of importance, has been alkaline paper,
which lasts much longer than acid based paper. Alkaline paper is manufactured
with fillers such as calcium carbonate, which bring the pH above 7.
An acidic paper like newsprint has a pH around 4.5 which becomes lower
once it is printed. The acid level tends to break down the paper and
it can deteriorate rapidly, which is why newspapers tend to yellow
and fall apart in time. Alkaline paper (a pH above 7) is said to be
permanent, but papers that have a neutral pH are still best for preserving
items like photographic albums and as matte boards for artwork.