Paper is a thin material mainly used for writing upon, printing upon or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets.
Paper is produced from its pulp either by paper machine (fourdrinier machine) ,or by handmade paper technique.
The Fourdrinier Machine is the basis for most modern papermaking. It is a mechanically automated machine, in which slurry is sprayed uniformly on moving wire bed which is sent to vacuum region and felt rolls to dry out water. It is then send to steam rollers to dry further giving paper.
Handmade paper is made manually from pulp by use of deckle &mold arrangement. Fibre slurry is first prepared which is then poured on mold of required paper size. It involves making a dilute suspension of fibres in water and allowing this suspension to drain through a mold so that a mat of randomly interwoven fibres is laid down. Water is removed from this mat of fibres by pressing and drying to make paper.
Handmade paper has more strength in all four directions irrespective of machine made which has less strength in machine direction. Handmade paper has good quality of watermarks.
Paper quality is defined by various parameters which depend on the materials used, type of manufacturing, and environmental conditions.
International Organisation of Standardisation (ISO) has given some clauses to standardise various quality of papers. These are:
FIELD | ISO Clause |
Sampling to determine average quality | ISO 186 |
Standard temp. and humidity and procedure for monitoring the atmosphere and conditioning of samples | ISO 187 |
Untrimmed sizes Designation and tolerances for primary and supplementary ranges, and indication of machine direction | ISO 217:2008 |
PHYSICAL PROPERTIES | |
Grammage | ISO 536 |
Caliper(thickness), density and specific.