Reference Book
Fiber strength:- Paper with longer fiber length has better resistance to tearing.
A sheet’s tear strength is proportional to the length of its fiber.
Finish:- It is the degree of smoothness of a paper’s surface. Example of different
finishes are antique finish, eggshell finish, vellum finish, machine finish,
embossed finish, matt finish, dull finish and gloss finish.
Pick resistance:- It is the ability of a paper to resist surface rupturing during
printing.
Whiteness and brightness:- Whiteness refers to the extent to which it reflects
nearly equal amount of RGB light from its surface. Brightness can be defined
as the percentage of striking light a surface reflects.
Substance weight:-The weight of a paper is measured by its substance weight
or basis weight. The substance weight is the weight of a ream of paper in a
specified size.
Flatness:- It is a measurement of how much the paper curls or become wavy.
Squareness:- A sheet’s squareness describes the sheet being exactly 90o at all
four corners. Squareness is important for sheets that will be printed with a
work and turn or work and tumble imposition.
Ink drying:- Variations in paper quality can result in slow ink drying.
Moisture absorbancy:- Paper is hygroscopic in nature. Paper absorbs moisture
from its sorroundings. It causes the cellulose fibers to expand in the direction
of its width and this results in change of dimension of paper.
Opacity:- Refers to the ability of paper to hide or mask a colour or object on
the back of the sheet. Poor opaciy causes show-through in which the image on
one side of a sheet of paper is seen on the other side.Paper classification, paper sizes & paper weight
Classification of paper based on grammage and structure
Paper is a tubular structure generated by natural agglutination and felting of
fibers and having a grammage of 7g/m^2 to 150 g/m^2. On the basis of the
composition of the pulp or raw material paper is divided into woodfree paper,
paper containing wood, paper containing waste paper and paper containing
rag.
Wood free paper is mainly produced from chemical pulp fibers and must contain
a maximum of 5% of ground wood pulp. Lot of printing and writing paper, as