We are giving below the definition in short of various properties of paper :

Brightness :
In paper industry the term " brightness " is expressed in points or % and it co- relates roughly with the whiteness of the sheet. However two white sheet of identical brightness may not appear identical to eye due to difference in color tint. Generally unbleached pulp have a brightness in order of 20 to 25 unbleached sulphite 55 to 65, white bleached paper and board 70 to 80. Very high brightness are sometimes required above 83 points but to obtain these without degradation of strength is costly.

Bulks :
Bulks is a term used to indicate volume or thickness in relation to weight , of the two papers of equal weight that which handles the thickness is said to be of better bulk .

Bursting strength :
It the indicates the force or pressure required to burst through a given area of paper. It is a complex function of tensile strength and stretch .

Breaking length :
It is a strength to weight ratio which indicates the length of a strip of paper required to cause the strip to break under its own weight .

Cleanliness :
It is one of the important physical properties of paper. This word is very much related with the presence of dirt in the paper .Paper should be free from dirt, shieves and spot.

Color :
Color of paper is one of the important optical properties of paper. It is defined as the psychological sensation produced in the brain of the observer by the action of visible light on the retina of eyes. With the aid of dyes and bleaching agents, the color of paper can be made brighter.

Folding resistance :
Folding resistance or endurance is a test which measures the amount of folding the paper will endure before it tensile strength falls below a standard value of 1kg . It is commonly measured in the number of double folds which the sheets will stand before the tensile strength is lowered below 1kg .

Calendaring and Supercalandaring :
The paper during the process of manufactured is passed through a stack of heavy metal rolls where it is calendared under high pressure. The calendaring is the done with object to increase the smoothness and finish of paper, to make the paper more uniform in thickness.

Machine and cross direction of paper :
Paper has a definite gain caused by (1) the greater orientation of fibers in the direction of travel of the paper machine (2) the greater strength orientation which results partly from the greater fiber alignment and partly from greater tension exerted in paper in this direction during drying. This grain direction is known as machine direction.
The cross direction is direction of paper at right angle to the machine direction.

Long grain paper is made when the shorter size is cut out of machine deckle and the short grain paper is made when the longer side is cut out of the machine deckle.

Moisture content :
It is defined as the %loss of weight of paper after even drying to constant weight at the temperature of 102 degree to 105 degree C. The percentage is normally expressed on the basis of the moist paper.

Opacity :
Opacity is a property of paper which is determined by the total amount of transmitted light. Opacity is taken to be the extent to which the sheet is impervious to the 'show through' of printed or written matter of one side to the other. Titanium oxide have and exceptionally high pacifying effect derived from the high index of refraction.

pH :
pH values relates to acidity or alkality of paper or board. A paper is said to be neutral when pH value is 5.5 . Paper having less than 5.5 pH value is acidic while paper more than 5.5 pH value is alkali.

Sizing :
Cellulose readily absorb water and solvents. Therefore unless they are sized they would behave like blotting paper and newsprint. Sizing makes paper resistant to various degrees, more resistant called as soft sized.

Tear :
Tearing test as certains the resistance of paper to tearing action after an initial tear .

Tensile strength :
It is a measure of resistance of paper to direct tension. It is defined as force required to break a strip to paper which has a specified length and width of 15 mm.

Thickness (or caliper) :
It is the distance between two circular planer substances, it is measured in a micrometer under a pressure of 8 to 9 lbs per square inch. The result are reported in thousand or ten thousand of an inch .
Wire and felt side of paper :
Paper has two sides, the wire and the felt side. The wire side is generally rough because of the pattern caused by wire marks. Paper is open or porous on wire side and closed or finer textured on the felt side. The difference in smoothness and porosity on the two side of the paper is referred to as two- sides.

Substances (or basis weight) :
Substances is the weight of a specified area of paper . In the metric system the unit for basis is expressed as number of grams per square meter (g/m2). In practice while all supplies in reel forms are specified on basis of grams per square meter, the supplies in sheet are indicated in kilograms per ream containing either 500, 480, 144, or 100 sheets.