What is the Porosity - What is porosity??

A measure of the void empty spaces within a material such as paper When fibres are bonded together to produce paper they create tiny passages that may penetrate completely through the sheet or only extend part of the way down Porosity can be controlled to an extent by binding the fibres together more tightly during manufacturing Porosity of paper is measured either by the time it takes for a particular quantity of air to pass through a sample using a Gurley densometre or how quickly air passes through a sample using a Sheffield porosimetre Porosity can determine how much adhesive or ink will soak into a sheet of paper A highly porous paper will have good adhesive or ink receptivity resulting in a high quality adhesive bond or print respectively Porous papers are ideal for high speed printing processes as when printing newspapers where the ink needs to be absorbed rapidly to reduce the risk of smudging However it can also result in strike-through Low porosity papers can lead to print smudging poor adhesion and usually have greater problems with dimensional stability due to issues with moisture content

Glossary

Hygroscopic - What does hygroscopic mean?

Definition of HYGROSCOPIC:

A property of materials and substances that causes them to attract and hold water molecules from their environment, either through absorption (a mass of water is taken into the material) or adsorption (water molecules adhere to the surface of the material). Hydroscopic materials take in or release water in order to reach equilibrium with the humidity of their environment. Various properties of the material may be altered by the presence of water molecules between its own molecules; it could change in size, or, if there is a difference in the moisture content of the two sides of a material, the material may curl. Paper is hygroscopic as are a variety of other materials including some salts and polymers.

Spilled coffee soaking into a sheet of paper; paper is a hygroscopic material, which means that it takes in water from its environment.

Here is the Harvard-style citation to use if you would like to reference this definition of the word hygroscopic:
Label Planet (2020) What does hygroscopic mean? | Hygroscopic Definition. Available at: https://www.labelplanet.co.uk/glossary/hygroscopic/ (Accessed: January 1, 2024).

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