Why Use Molded Pulp Packaging?
- Acid Free (Neutral pH):
- Papers that are without acid in the pulp. Acid free
papers have a pH of 7.0. If prepared properly, papers made from any fiber
can be acid free.
The transfer of acid from an acidic material to a less
acidic or neutral-pH material. Occurs when neutral materials are exposed
to atmospheric pollutants or when two paper materials come in contact.
Acid can also migrate from adhesives, boards, endpapers, protective
tissues, paper covers, acidic art supplies, and memorabilia.
An astringent crystalline substance used in rosin
sizing to hold paper fibers together; responsible for introducing acid
into the paper.
A printing paper with a rough finish but good printing
surface, valued in book printing for its high volume characteristics.
A paper with long-standing qualities, acid free,
lignin free, usually with good color retention.
The neutralizing of acids in paper by adding an
alkaline substance (usually calcium carbonate or magnesium carbonate) into
the paper pulp. The buffer acts as a protection from the acid in the paper
or from pollution in the environment.
- The thickness of paper expressed in thousands of an
The chief constituent of the cell walls of all plants.
All plants contain tissue that, when properly processed, will yield
cellulose. Cotton in its raw state contains about 91% and is the purest
form of natural cellulose. Other sources for papermaking include hemp
(77%), softwoods & hardwoods (57% to 65%), and kozo (66% to 77%).
- Cold Pressed:
A paper surface with slight texture produced by
pressing the finished sheet between cold cylinders.
Fibers that adhere to cottonseed after ginning. Used
as raw material to produce pulp for cotton fiber content papers.
- Deckle Edge:
The feathery edge which is the result of the natural
run-off of wet pulp when making handmade and mouldmade paper, or the
result of sheets being torn when wet. The edge is simulated in machine
made papers by cutting them with a stream of water when still wet.
- Dimensional Stability:
The degree to which a paper will maintain its size and
shape when subjected to changes in moisture content and relative humidity.
- Felt Finish:
Surface characteristics of paper formed at the wet end
of a paper machine, using woven wool or synthetic felts with distinctive
patterns to create a similar texture in the finish sheets.
- Felt Side:
- The top side of the paper, usually recommended for
best printing results.
- The slender, thread-like cellulose structures that
cohere to form a sheet of paper.
A generic term to describe the non-oxidizing clays or
minerals added to the pulp at the beater stage to improve paper density.
- The cutting, sorting, trimming and packing of paper.
The arrangement of fibers in a sheet of paper; can be
seen by holding it up to a light source.
A bast fiber from the gampi tree used in Japanese
papermaking to yield a smooth, strong sheet.
- Direction of fibers in a sheet of paper. Long grain
describes fibers running parallel to the longest side of a sheet. short
grain running parallel to the short side.
- Grams per square meter:
The gram weight of a hypothetical square meter of a
particular type of paper, a good comparative measure because it does not
vary with sheet size.
- Handmade Paper:
Paper made by hand using a mould (a frame covered with
a flat, rigid screen or flexible screen). In both cases the mould is
covered by a flat frame called a deckle, to contain the run-off of wet
pulp, dipped into a vat of wet pulp, shaken to distribute the fibers
evenly and drained of its excess water. The wet mat of fibers remaining in
the newly formed sheet is then dried against blankets & may be hot
pressed, cold pressed, or air dried.
- Hot Pressed:
A paper surface that is smooth, produced by pressing a
finished sheet through hot cylinders.
- High Alpha Cellulose:
A very pure form of wood pulp which is considered to
have the same longevity as cotton or other plant fibers.
The most common fiber used in Japanese papermaking, it
comes from the mulberry tree. A long, tough fiber that produces strong,
- Laid Papers:
Papers with a "grid" pattern in the sheet, resulting
from the pulp resting against wires on the papermaking mould screen.
"Laid" lines are closely spaced while "chain" lines are farther apart &
run parallel with the grain direction of the sheet, important when folding
papers, especially to bookbinders.
- The speed at which a pigment or colored paper fades in
A component of the cell walls of plants that occurs
naturally, along with cellulose. Lignin is largely responsible for the
strength and rigidity of plants, but its presence in paper is believed to
contribute to chemical degradation. To a large extent, Lignin can be
removed during manufacturing.
- Machinemade Paper:
Paper made on a very rapid running machine called a "Fourdrinier",
producing consistent quantities of sheets or rolls.
- A pure adhesive which dries clear. Suitable for
A bast fiber used in Japanese papermaking that yields
a soft, absorbent and lustrous quality.
- Mouldmade Paper:
Paper made by a slowly rotating machine called a
cylinder mould that simulates the hand-papermaking process. Fibers become
more randomly intertwined than in machinemade papers, producing a
stronger, more flexible sheet or roll.
- A slight surface texture of some writing surfaces.
Animal skins or linings stretched and prepared as
writing/painting surfaces. Produces a smooth, buttery surface.
A single layer of paper. A term used when several
sheets of paper are laminated together to form a board.
- Any cellulose plant fiber cleaned and beaten into a
wet mixture used to form sheets of paper.
In chemistry, pH is a measure of the concentration of
hydrogen ions in a solution, which is a measure of acidity or alkalinity.
The pH scale runs from 0 to 14 and each number indicates a ten fold
increase. Seven is pH neutral: numbers below 7 indicate increasing
acidity, with 1 being the most acid. Numbers above 7 indicate increased
alkalinity with 14 being the most alkaline. Paper with a pH below 5 is
considered highly acidic. Buffered papers typically have a pH between 8.5
- PVA (Polyvinylacetate):
An archival white glue that is stronger than gel
medium. It mixes well with gloss medium. Transparent even after many coats
and remains water soluble. Mixed with gel it becomes water resistant.
Formerly the principal raw material used in the making
process; often meaning cotton rags. Rag content describes the amount of
cotton fiber relative to the total amount of material used in the pulp.
"Rag content" is not widely used (or is a misnomer) today as more and more
high quality paper is made not from rag but from linters.
- Rice Paper:
A common misnomer used to describe Oriental papers.
There are no papers made from rice, although rice starch was traditionally
used to size papers made of Kozo (mulberry plant), Gampi, or Mitsumata.
A heavily textured paper surface produced by placing
wet sheets of paper against textured blankets or air drying (or both).
- Size or Sizing:
The process by which gelatin rosin, starch or other
synthetic substance is added to paper to provide resistence to the
absorption of moisture or eliminating ink feathering and bleed through.
Sizing added to the beater or vat of pulp is known as internal sizing.
After a sheet is formed, it may be either surface sized (painted or
brushed on the surface), or tub sized (immersed in a bath).
Sulphite pulp is produced from the wood of coniferous
trees. Wood chips are cooked in calcium bisulphate or sodium sulphite, and
bleached, producing fairly long strong fibers. Since the end of the 1860's
until recent years, it has been the most widely used pulp in America. In
fact, the term"sulphite" has become generic and is still accurately used
to describe any paper made from wood in distinction from papers made from
cotton or other fibers. Sulphite pulp is available in a range of grades up
to pure alpha cellulose.
A very slight surface texture of paper preferred for
dry media such as charcoal and pastel.
A paper surface that is finely textural. Vellum is
also used to designate heavy weight, translucent drawing of drafting
- A paper with little or no sizing. Very absorbent.
The translucent design or name easily visible when a
sheet is held to the light. A design is sewn onto the papermaking screen
with raised wire. When the sheet is formed, the pulp settles in a thinner
layer over the wire design.
The continuous ribbon of paper, in its
full width, during any stage of its progress through the paper machine.
- Wheat Paste:
- A preferred archival adhesive for book arts.
- Wove paper:
Papers which show no fine "laid" lines running through
the sheet when held to the light.