S
SCUM
Traces of printing ink that temporarily adhere, during litho printing, to the non-image area of the plate due to its inability to reject ink.
SECURITY PAPER
Paper that includes identification features such as metallic strips and watermarks to assist in detecting fraud and to prevent counterfeiting.
SELF-ADHESIVE PAPER
Used mainly for labeling purposes, this grade has a self-adhesive coating on one side and a surface suitable for printing on the other. The adhesive is protected by a laminate that enables the sheet to be fed through printers or printing machines. The laminate is subsequently stripped when the label is applied.
SEMI-CHEMICAL PULP
Pulp obtained by partial removal from the raw material of those non-cellulosic components that can be removed by a direct chemical treatment, e.g., cooking, to resolve the fibers. Some subsequent mechanical treatment is necessary.
SET-OFF
The undesirable transfer of printing ink from a print to a facing surface.
SHIVES
Coarse fragments of fibrous materials present in pulp or paper, resulting from incomplete resolution during pulping.
SHORT GRAIN
The fibers in a web of paper naturally take up an alignment roughly parallel to the direction of travel of the web on the papermaking machine; this becomes the grain direction. When cut, the paper’s grain direction may be parallel either to the long edge of the finished sheet (when it is called long grain) or the short edge (short grain). Papers are normally stocked in long grain form; short grain being supplied to special order. The grain direction affects the stiffness in a particular dimension and must be taken into account when planning a job that needs to be folded, as paper generally folds easier with the grain.
SHOW-THROUGH
The degree to which a printed film is visible through paper due to the low fuzziness of the paper.
SIDELAY
Device on the feed board of a printing machine for controlling the lateral alignment of the printing paper
SIDE-RUN
(1) A narrow reel removed from a web while processing, the width of which is less than the size ordered, but is large enough to permit its use for purposes other than re-pulping. (2) An additional part of an order placed in order to better utilize the maximum trimmed machine width of the making machine.
SIZING
This process can be applied either on the surface of the sheet or in the sheet. In the first case, starch is applied to the surface to increase its strength and to resist the penetration of oil-based inks (this process is carried out at the size press, which is about two-thirds of the way down the dry end). In the second case chemicals are added to the stock at the pulping stage before the sheet is formed. This is called internal or engine sizing and its purpose is to stop penetration of water-based inks into the sheet.
SLITTING
Cutting paper by the use of cutting wheel. Paper may be slit into smaller sheets or a web of paper may be slit into narrower rolls.
SMOOTHNESS
The surface smoothness of paper is measured by the Bendtsen smoothness test. The test measures the amount of air escaping between an annular ring and the material surface, and results are measured in ml/min. Papers having a value higher than 50 are usually referred to as Matte, below 50 as Silk (sometimes called Satin or Velvet).
SOFT CALENDERING
A relatively new method of smoothing paper. Soft calenders are more compact than other calenders and adopt a system whereby the web is passed between steel and hard rubber rolls. The method enables a wide variety of finishes between gloss and matt and the retention of bulk.
SOFTWOOD PULP
Pulp obtained from the wood of coniferous trees by various processes.
SOLID BOARD
A board comprising a single furnish layer. Solid board has inherent strength due to its density. It still has qualities that make it suitable for use with food products where moisture can be an issue. Some of the suitable uses for solid board are flat pack “pop-up” cartons, packaging for frozen foods (polythene coated), backing cards for blister packs, corner glued boxes and lids , greetings cards and business cards and laminating to corrugated board (in high quality litho-printed form).
SOLID FIBERBOARD
A board, which may be pasted or unpasted, and often incorporating a lining of Kraft or other strong furnish, intended and suitable for the manufacture of fiberboard packing cases and drums.
SOLVENT-COATED PAPER
Paper coated by any suitable coating process with resins or plastics dissolved in volatile solvents that are subsequently evaporated.
SPLICE
Joint in a web of paper in or nearly in the cross direction, made either by an adhesive or an adhesive strip, (a) to obtain a reel of the desired length, or (b) to permit, for example in a converting machine, a continuous operation between the end of one reel and the beginning of the next.
SPREAD COATING
A procedure of coating a web of paper by means of a vertical plate restraining a pond of viscous coating material, for example resins, plastics or adhesives, which is drawn through an adjustable gap between the plate and the paper by the forward movement of the web over a horizontal support
STACK
A type of calender, usually situated at the end of the making machine, of which the rolls are of metal only.
STOCK
The wet pulp before it is fed onto a papermaking machine, or during the papermaking processes before it becomes a sheet of paper. Contains around 99% water and 1% fiber.
STOCK PREPARATION
Collective term for all handling necessary for the preparation of the stock before it reaches the making machine.
STRAW PULP
Papermaking pulp obtained from cereal straws by various processes.
STRIKE-THROUGH
The effect seen on the reverse side of the sheet due to excess penetration of printing ink or vehicle into or through the paper.
SUBSTANCE
The weight of paper or board, shown by scales, taken from a sample. The weight is nowadays almost entirely defined by grammage per square meter of a single sheet (g/m2).
SULPHATE PULP
Pulp obtained by cooking the raw material with a mixture consisting of caustic soda, sodium sulphide and possible other compounds, such as black liquor.
SULPHITE PULP
Pulp achieved by cooking the raw material with a bisulphite liquor.
SUPERCALENDERED FINISH (SC)
A surface finish on paper which may vary from relatively dull but smooth to highly glazed, manufactured by passing dampened paper through a supercalender stack. This is broadly similar to a machine calender stack except that it is separate from the papermaking machine and some of the rolls are of compressed fiber.
SWORD HYGROSCOPE
Portable testing instrument designed for insertion into a stack of paper to assess whether the moisture content of the paper is in balance with that of the surrounding atmosphere.
SYNTHETIC PAPER
Paper manufactured by conventional means from furnishes comprising substantially or wholly synthetic fibers. Also sheet material, resembling paper, made from synthetic filaments by other means, e.g., spin bonding. Plastics material in sheet form, surface treated to render it suitable for commercial graphic printing.
