BACKWATER
The liquid that passes through the forming surface when stock is deposited upon it. It is essentially water, but generally contains dissolved matter or suspended matter such as fines, filler, etc. Backwater is normally recirculated within the papermaking process, or sent to a treatment plant for the recovery of materials in suspension.

BAGASSE PULP
Pulp obtained by chemical means from bagasse, the residue after extracting the juice from sugar cane.

BAMBOO PULP
Pulp obtained by chemical means from the stems of bamboo, a type of grass common to Asiatic countries.

BANKS AND BONDS
A range of printing and writing papers, the better qualities of which were at one time made largely from rags. The heavier substance papers, above a substance of about 60g/m2, are often used for correspondence and letterheads and are known as bonds. The lighter weights, called banks, are used largely for file copy papers but have less use today with the introduction of the automated office.

BARK WASTE
A major source of energy for pulp mills. Raw timber is debarked before chipping with the bark being recovered and burnt at a steam power plant.

BASE PAPER
Paper intended to be converted, e.g., by a coating process or by impregnation. The term sometimes also used for paper to which a layer of other material (aluminum, plastic, etc.) is bonded. Also called Body Paper or Rawstock.

BEATING OR REFINING
The mechanical treatment of fibrous materials in a beater or refiner to modify certain of their characteristics in order to give them the properties necessary for the manufacture of a desired quality of paper.

BIBLE PAPER
Very thin printing papers. Originally made specifically for bibles and prayer books, this grade of paper is also used for other commercial purposes - such as dictionaries - where many pages are required with an overall low volume. Bible paper is also known as India paper.

BINDER
The adhesive used to stick layers of coating together as well as to the paper or board surface. The most frequently used binder is starch, but synthetic binders are also used to give improved performance.

BIODEGRADABLE
A substance that will decompose as the result of action by bacteria and other living organisms.

BIOLOGICAL OXYGEN DEMAND (BOD)
This expresses the amount of dissolved oxygen consumed by microorganisms as they decompose organic material in polluted or natural water. The higher the amount of decomposable material, the higher the BOD value.

BIOLOGICAL WASTE WATER TREATMENT
A variety of methods used by pulp and paper mills for purifying their wastewater (such as the activated sludge method) in which natural microorganisms decompose the organic substances. The organisms constitute a nutrient cycle consisting of bacteria, protozoa and higher organisms. The method reduces the biological oxygen demand by over 95% and removes about 50% of the organic compounds from effluent, organic chlorine compounds included.

BLACKENING
Defect associated with calendered paper occurring as unintended local areas of apparently darker or grayer color due, for example, to the paper being too damp when passed through the calender.

BLADE COATED PAPER
Paper coated by a process in which the freshly applied wet coating is smoothed and the excess removed by a thin, flexible metal blade that bears on the coated surface.

BLANKET CYLINDER
The cylinder on a printing machine covered with a rubber (or similar) blanket, which conveys the image from the plate to the sheet.

BLANKET-TO-BLANKET MACHINE
A printing machine in which the blanket cylinders act as opposing impression cylinders, allowing both sides of the web or sheet to be printed simultaneously.

BLEED
The part of a printed image beyond the area to which the finished print will be cut.

BLISTER PACK
This term describes a packaging system that is a combination of board and plastics. The product is sealed to the board by a transparent plastic film. This system is often used for small products of difficult shapes and sizes.

BLOTTINGS
Highly absorbent papers that can be watermarked. With the advent of the ballpoint pen, the original use where handwriting ink is absorbed has greatly reduced demand.

BOARD
Heavy weight paper. The line of demarcation between paper and board is indeterminate. For many purposes it is taken as 220 or 225g/m2, but many products below these levels are described, commercially, as board.

BOD7
The biological oxygen demand of a wastewater sample, measured over seven days' exposure (also. BOD5, BOD10).

BOND
See Banks and Bonds

BREAKING LENGTH
The calculated limiting length of a strip of paper of any uniform width, beyond which, if such a strip were suspended by one end, it would break by its own mass.

BROKE
Paper and pieces of paper arising at any point in the mill that are suitable only for repulping, e.g., wet paper removed from the paper machine or dry paper arising as trimmings, faulty paper, etc.

BRUSH COATING
A method of coating a web of paper in which the applied coating slip is distributed and smoothed by means of brushes, some stationary and some oscillating across the web.

BULK-PACKED ON PALLETS (BPOP)
A method of packing paper in which the sheets are not wrapped in parcels but stacked on the pallet, tabbed at the required intervals to indicate quantity and over-wrapped.

BULKY MECHANICAL
A mechanical paper made to a specific caliper as opposed to a fixed grammage. Typical calipers are 102 and 127 microns. This type of paper, used mainly for mass-market paperback books, also has several uses when converted, such as cash register rolls.

BULKY PAPER
Paper that appears to be thick in relation to its grammage.

BURST FACTOR
The quotient of the bursting strength of a paper and its oven-dry grammage as defined in the standard method of test.

BURST INDEX
The quotient of the bursting strength of a paper and its grammage in the conditioned state as defined in the standard method of test.

BURSTING STRENGTH
The pressure necessary to rupture a sample of paper fixed horizontally between two ring clamps.