Have each person tear a sheet of paper. “trick” them by doing a grain short sheet.
&lt;number&gt; When paper emerges from the last dryer, some grades are ready to be rewound, wrapped, and shipped. But some paper from the machine goes though an additional finishing step off line. Some papers, like mattes and silks, are finished in line on the PM and are calendered. Most of our gloss and dull papers go off line to a supercalender. A supercalender is a series of resilient rolls set one on top of the other. Alternately metal/steel and soft/cotton resilient rolls. Paper enters the stack at the top and the fibers are polished and compressed; it is compacted and smoothed progressively as it travels down the stack. As the paper moves between the rolls, they exert varying degrees of pressure on the paper. The hard metal rolls press into the resilient rolls at the nip, producing a polishing action that imparts varying degrees of smoothness and gloss to the paper. This process, combined with heat, is known as calendering. The degree of smoothness and gloss is determined by the amount of pressure, surface of the rolls, and number of nips, or passes through the calender. In some processes, as in our dull process, we use embossing, which gives the paper a pattern finish. The metal roll carries the embossed pattern. When the paper passes between the embossed roll and the cotton roll, the pattern is imparted onto the paper. Coating chemistry dictates calendering outcome. Heat not a factor with this process. Not enough heat generated by friction to impact.
&lt;number&gt; It is commonly used to show high amounts of detail. Bright colors.
&lt;number&gt; End up with a lower sheen than gloss or dull paper. Appropriate for a wide variety of printed materials; common in books. Printed ink gloss on matte papers is better than on uncoated paper. Still low because ink pigments don’t lie evenly, and some of the resins sink into the sheet.
&lt;number&gt; (As noted.) In our mills, we use a microscopic design to impart a uniform pattern on the sheets. This pattern results in a low gloss surface.
&lt;number&gt; As above.
&lt;number&gt; Note that imported coated papers in NA are manufactured to NA standards. Note differences in thickness of coating and fiber from different markets NA - most fiber least (highest quality) coating E - least fiber/most coating A - mid range for fiber and coating
&lt;number&gt; Premium Uncoated A smooth text and cover sheet finish that softens the image and enhances the tactile quality of the surface, adding dimension to touchable materials.
&lt;number&gt; What this means to you! Smoothness enhances reproduction because it reflects light back to the viewer in straighter lines (specular) , which keeps the images sharp and clear. Rougher surface: Solids may look uneven Scatters light, diffusing detail, graying colors, sometimes changing their hue. Critical Color: Products, Corporate Colors Pleasing Color: Everything else. Food, Flowers, People, etc.
Paper Properties and Their Impact
on the Printing Process
Why is Knowing Paper Important to you?Why is Knowing Paper Important to you?
1) Paper and other
substrates on which an
image is printed can
represent 25-55% of
the final cost of a
2) Having a working
that the paper selected
is the most appropriate
and cost effective for
Basics of Paper ManufacturingBasics of Paper Manufacturing
2. Logging – debarking
3. Pulp refining
4. Forming Section (wet
end), Press Section (water
removed), Drying Section
(sets moisture levels)
5. Calendaring (final stages
for smoothness, etc)
6. Cutting down the 40,000 lb
plus rolls ready for
finishing (rolls or sheets)
Paper Machines are the length of football fields!!!Paper Machines are the length of football fields!!!
Key Properties of PaperKey Properties of Paper
Wood Fibers Used in Paper ManufacturingWood Fibers Used in Paper Manufacturing
The fibers used in paper manufacturing
play a key part in what happens to it later
•Weaker, yet smoother
•Stronger, yet rough
Fibers Used in Paper ManufacturingFibers Used in Paper Manufacturing
Paper can be made from MANY sources, but wood
fibers are used more often
Other paper fibers sources can include:
• Cotton and other plants (i.e. hemp)
• Recycled fibers
• Even old jeans!
Basis Weight of Paper ---- Huh?Basis Weight of Paper ---- Huh?
Basis Weight is paper weight in pounds of a ream (500
sheets) in it’s basic size
Web Printers purchase paper by weight (pounds) in rolls.
Sheet fed printers typically order by number of sheets
needed for the job.
The basic size for Book papers is 25” x 38”. The
measurement of basis weight for book paper would be
calculated by taking 500 sheets each measuring 25” x
38” and placing it on a scale. If the weight of the 500
sheets was 50lb., we would call that paper 50 lb. Book.
If the weight was 60 lb. it would be 60 lb. book.
Basis Weight Types – Basic SizesBasis Weight Types – Basic Sizes
1) Cover (20” x 26”)
a. Heavy weight papers
used for book covers,
advertising, direct mail,
2) Index (22 ½” x 28 ½”
and 25 ½“ x 30 ½ “)
a. Usually available in
smooth and vellum
finishes. Used in file
folders, index cards,
3) Tag (24” x 36”)
a. Smoother surface than
index, making it ideal
for high-speed folding,
3) Bond (17” x 22”)
a. Commonly used for
letters and business
forms. Example: paper
in your books is 20#
Basis Weight Types – Basic SizesBasis Weight Types – Basic Sizes
5) Board (22 ½” x 28 ½”)
a. One of the board
grades, with a softer
surface than index or
tag. Used for POP,
signage, book covers
(soft), advertising etc.
6) (25” x 38”)
a. Coated Book
b. Uncoated Book
Much easier outside the U.S.…
They use only one Basis Weight.
Basis Weight as compared to CaliperBasis Weight as compared to Caliper
Basis weight is the
weight in lbs of a ream of
paper in its’ basic size
Caliper is the
thickness of the paper
Formation is the physical distribution and orientation of
fibers and other solid constituents in the structure of a
sheet of paper which affects the appearance and other
Formation is also referred to as “look through”
because the formation can sometimes be observed by
looking through the sheet.
Formation can have a big impact on print
a. Ink Mottle - A “wild” formed sheet will result in
the ink absorbing into the structure unevenly
which then causes the ink to day with a
b. Ink Show-Through (Printed Opacity) -
If a sheet is “wild” with areas of fiber
surrounded by areas of no or little fiber,
ink will bleed at differing rates resulting
in a strong “blotchy” ink show-through.
Surface SizingSurface Sizing
Surface is a key to good press runnability!
a. Uncoated papers need to “seal” the sheet to reduce
press contamination (fiber, debris, etc.).
b. Sizing used for uncoated paper consists of a starch
applied to the paper during the paper making
c. Various types of starches are used:
Good surface sizing is
critical to achieve good
Surface SizingSurface Sizing
Starch is applied by a simple “coating device” located
between the two drying sections of the paper machine.
There are several types used by paper makers to
applied starch. A typical size press would look like
Size Press Rolls
Optical PropertiesOptical Properties
1) There are five main optical properties that
influence the visual perspective of a printed sheet:
Opacity relates to the
show-through of the
printed image from the
opposite side of the
sheet, or the sheet
Brightness affects the contrast, brilliance, snap or sparkle
of the printed sheet. It is the percent of reflectance at a
standard single wavelength.
a. Don’t confuse “whiteness” with “brightness”.
b. Whiteness is the amount of Red, Blue and Green
reflectance and that will be discussed shortly
AF&PA Brightness ComparisonAF&PA Brightness Comparison
81.9 and below81.9 and below
91 +91 +NO.1NO.1
GE BRIGHTNESSGE BRIGHTNESS
1) Whiteness is the ratio of Red, Green and Blue
a. An attribute of a diffusing surface which denotes its
similarity in color to preferred or standard white.
A psychological attribute of a color stimulus. A
“white” color stimulus is perceived as void or any
hue or grayness.
a. White can be in many different hues.
Known as “cold” if on the blue side.
Known as “warm” if on the red side.
1) Gloss is the relative amount of incident light
reflected from a surface.
a. Paper Gloss - Degree to which a paper surface
b. Printed Gloss - Degree to which a printed ink
2) Paper Gloss is attained by the paper maker
through calendering and pigments.
a. The higher the calendaring, the higher the gloss.
Pressure and heat
combine to make
the sheet shinier
However, the more
you calendar, the
thinner the sheet
Coated Paper Finish ExamplesCoated Paper Finish Examples
Finish Calendering Paper Gloss Surface Suggested
Matte None Not apparent Rough/toothy,
Dull Minimal Very Low Smooth, non-
Black & White
Satin/Velvet Light Low -
soft to the
Silk Light Moderate Smooth and
silky to the
Fine art, skin
Gloss High High Smooth, shiny,
Gloss Finished SurfaceGloss Finished Surface
Calendared using smooth and
polished steel rolls
Highest printed ink gloss
Highest plain paper gloss of
coated finishes -- reflective
Highest ink hold-out, lowest dot
Best for showing fine detail
Matte Finished SurfaceMatte Finished Surface
a. Lowest paper gloss
b. Lowest printed ink gloss
c. Greatest amount of contrast
between paper and ink
Replicates look and feel of uncoated
End Uses: Text, charts, anywhere to
minimize eyestrain, writeable
Silk / Dull Finished SurfaceSilk / Dull Finished Surface
pattern from imparted by
Excellent ink holdout for
sharp halftone reproduction
Richer halftones and solids
Velvet Finished SurfaceVelvet Finished Surface
Coating formula and on line
calendaring technique produce a
smooth, low gloss paper
Looks like a dull -- prints like a gloss
Higher paper gloss than a dull
Similar coat weight to gloss
Smoother, harder surface than a dull
More uniform printing surface than a
Distinctive, silky feel
A.K.A. Satin, Suede
Global Coated Papers: Worlds of DifferenceGlobal Coated Papers: Worlds of Difference
North American AsianEuropean
Uncoated versus Coated PapersUncoated versus Coated Papers
Measures texture and topography
Necessary for continuous, non-
mottled ink film
Higher ink gloss
More pure ink color/broader tonal
More accurate reproduction
Greater detail for critical color
1) Strength of paper is more dependent on the nature of
its fiber than its thickness.
a. High bursting strength is achieved by closely
intermingling long pulp fibers during the forming of
the sheet on the paper machine.
b. Fibers are long and tear in the cross machine
direction is always higher than tear in the machine
This is because the greatest number of fibers lie
across the path of the cross machine.
a. Tear strength is important when producing a sheet
with perforations. The “perf” should not fall apart of
be difficult to separate.
Stretch is the amount of distortion paper undergoes
under tensile strain. Stretch is generally much greater
in the cross direction than in the machine direction.
a. Excessive stretch with web or sheetfed papers
will result in poor registration or fanning problems.
The Moisture content is the percent of moisture found
in the finished paper.
a. Can range from a low of 4.0% to a high of 7.0%.
b. Heat-set web paper with low moisture (< 5.0%) will
dry out in the heatset oven causing cracking at the
1 ton of paper at 5% moisture level will contain 100
lbs. of water!
Remember earlier when we talked about the paper
machine? Paper is 95 to 98% water as it enters
the paper machine! Moisture in paper plays a
part from the beginning all the way through the
Paper likes to come to equilibrium with its environment.
a. Paper brought into a humid pressroom absorbs
moisture at the edges while the rest of the pile or roll
(towards the center) will remain unchanged.
b. As this process occurs, the edges containing more
moisture will increase in size resulting in wavy edges.
c. Paper brought into a dry pressroom will give up
moisture, at the edges first, shrinking the paper
resulting in tight edges.
This will result in wrinkles, fanning and bad registration.
Specialty Grades of PaperSpecialty Grades of Paper
Pressure Sensitive (i.e. “sticky back”)
Educational ResourcesEducational Resources
1) Spicers Paper
a. Environmental calculator
b. other tools
2) International Paper Pocket Pal
3) The “Coated U” from Appleton
4) Sappi Standards
5) Paper mill swatch books
6) Many more!
Corporate Office 800-774-2377 or 562-698-1199
Los Angeles 800-774-2377 or 562-698-1199
Las Vegas 702-736-4441
San Francisco 866-774-2377
Portland 800-452-8401 or 503-405-0100
Seattle 253-518-0015 or 800-231-5136
Kansas City 888-333-0055
St. Louis 314-801-6100
Salt Lake City 801-364-0113 or 866-403-6609