The binding of booklets or other printed materials by stapling the pages on the folded spine; also called saddle wire.
Satin Finish
A smooth, delicately embossed finished paper with sheen. Also called Silk.
Sawtooth
The effect of a stencil that leaves a printed image that conforms to the mesh of the fabric rather that the desired clean contour of the image.
SBS (Solid Bleached Sulphate)
A type of heavyweight board that is a single thickness run on a Fourdrinier paper machine using sulphate produced pulp.
Scoring
To impress paper with a rule for the purpose of making folding easier.
Screen Angles
Technique used in 4-colour printing which sets halftone screens at various angles to avoid moir patterns.
Seediness
A defect in a varnish caused by small particles which sometime become visible by transmitted light.
Self Cover
A cover made out of the same paper stock as the internal sheets.
Set-Off
Where undried ink is passed from the image on one sheet to the reverse of the next sheet in the pile.
SFI
Sustainable Forestry Initiative. A North American forest certification scheme, now endorsed by the PEFC.
Shore Hardness
Determination of hardness of substrate by measuring rebound of a hammer.
Shore Hardness
Determination of hardness of substrate by measuring rebound of a hammer.
Show-Through
The undesirable condition in which the printing on the reverse side of a sheet can be seen through the sheet under normal lighting conditions.
Side Stitch
To staple sheets or signatures on the side closest to the spine.
Silk Finish
See Satin Finish.
Size
Non-fibrous materials used in papermaking to control the absorbency of paper. Rosin, alum, starch and gelatin are the most commonly used.
Size or Sizing
The process by which gelatin rosin, starch or other synthetic substance is added to paper to provide resistance to the absorption of moisture or eliminating ink feathering and bleed through. Sizing added to the beater or vat of pulp is known as internal sizing. After a sheet is formed, it may be either surface sized (painted or brushed on the surface), or tub sized (immersed in a bath).
Size Press
Section of paper machine where surface treatments are applied to the sheet of paper to give it special qualities. Normally comprised of a pair of rolls towards the end of the dryer train between which the dry or partially dry web is passed, and into the nip of which a liquid, usually starch, is applied to impart strength to the sheet. Sometimes a chemical may be added to produce a water-resistant sheet.
Smoothness
Texture of the surface of paper. Also called its finish. Generally determined with a tester which measures time required for a given volume of air to flow between the surfaces of the paper sample and a piece of optically-flat glass under standard loading conditions.
SO2
Sulphur Dioxide. Formed during the combustion of fuels containing sulphur (such as oil and coal). Sulphur dioxide contributes to the acidification of soil and water.
Solvent
Any dissolving, thinning or reducing agent.
Spot Colour
A solid colour, such as those specified by Pantone colour System; the opposite of a process colour.
Squeegee
A tool for applying application tape and graphics
Stability
The quality of paper to maintain its original size when it undergoes pressure and moisture changes.
Starch
Material used as a surface or internal additive to provide strength.
Static
Electricity generated by friction as paper comes into contact on press with other paper, metal, wood, etc; the result of insufficient moisture in paper. Static causes the sheets to be attracted to each other, causing feeding and jogging problems.
Stiffness
Rigidity, resistance to bending and inflexibility.
Stock
In papermaking, refers to the wet pulp before it is fed on to a papermaking machine, or during the papermaking processes before it becomes a sheet of paper; contains around 99% water and 1% fibre. In graphic arts, stock means "paper".
Streaks
Elongated defects in a printed image.
Stretch
The "give" of a sheet of paper as it undergoes tensile pressure.
Sublimation
The process whereby certain dyes change directly from a solid to a vapour and back again to a solid by the application of heat.
Substrate
The material (usually paper, plastic or metal) upon which an image is reproduced.
Sulphate Pulp
Paper pulp from wood chips and pressure-cooked in a solution of caustic soda and sodium sulphide. Also known as kraft.
Sulphite
Sulphite pulp is produced from the wood of coniferous trees. Wood chips are cooked in calcium bisulphate or sodium sulphite, and bleached, producing fairly long strong fibres. Since the end of the 1860's until recent years, it has been the most widely used pulp in America. In fact, the term "sulphite" has become generic and is still accurately used to describe any paper made from wood in distinction from papers made from cotton or other fibres. Sulphite pulp is available in a range of grades up to pure alpha cellulose.
Sulphite Pulp
Paper pulp made from wood chips cooked under pressure in a solution of bi-sulphite of lime.
Supercalender (SC)
Machine for giving paper a very smooth surface by passing it through a series of alternate metal and composition rolls, revolving with high speed and pressure.
Surface Tension
The property (measured in dynes per centimetre) by which all liquids through contraction of the surface tend to bring the contained volume into a form having the least area. If an ink is to be compatible with a substrate, the surface tension of the ink must be close to that of the substrate.
Sustainable Development
Development which meets the needs of the present without compromising the ability of future generations to meet their own needs.
