In our business, it is a necessity to know basic paper and printing terms. Use the glossary for a quick reference or browse it to refresh your knowledge.
Select from the general listing below:
saddle stitching/wire
In binding, staples (formed from a continuous wire) driven through the back fold of a booklet, clinched in the middle, and enabling the booklet to open out flat. The same type of binding can be accomplished with a stapler, using pre-formed staples.
safety paper
A treated paper which when writing or printing on the paper is altered, the alteration attempt will leave a noticeable smudge, discoloration, or other evidence of change. This type of paper might be used for making checks or other documents to discourage such alterations.
sales book
Set of forms bound into a book, usually for ease of writing.
satin finish
A finish lacking gloss, generally intermediate to a matte finish and a dull finish. See also <i>gloss</i>.
save-all
A device on the paper machine which screens paper fibers from water, to save pulp which might otherwise be lost to the sewer.
scale
Foreign materials from the paper making or converting operations deposited on the web after it is formed, and can be starch or coating materials broken loose from the sheet, and redeposited. Scale in the printing operation can adhere to the blanket and transfer to the plate causing defects in the printed piece. The terms calender scale and coating scale are often used in relation to this defect, implying where in the paper making process the scale was deposited on the sheet.
scanning
In printing plate preparation, an electronic method, based on point by point scanning of color separations and tonal gradations under computer control.
score
The process and the resulting line mechanically impressed into a heavy sheet of paper or board, to pre-stress the fold line and facilitate folding or improve the appearance of the fold. Most effectively done with the grain of the paper, and is absolutely necessary with heavier basis weight paper.
scrap in roll
Trim or scrap paper wound into the roll of paper. The scrap may or may not be protruding from the ends of the roll.
screen
The ruling (usually expressed as lines per inch, i.e., 120 lpi, 133 lpi, 150 lpi) used to determine the dots per unit area in developing tonal values in the printed piece. Up to the point of "dot gain", the higher the screen, the finer the lines per inch, the greater the fineness of detail in the printed piece. See also <i>stochastic screening</i>.
screen angles
In color reproduction, the halftone screens are rotated with relation to one another, to avoid undesirable moiré patterns. The angles usually used are black 45 degrees, magenta 75 degrees, yellow 90 degrees, and cyan 105 degrees.
screen printing
A form of porous printing. The process by which the image area is created by forcing ink through a "screen" or mesh, created by blocking off all areas in the "screen" where no image is to be formed; an example would be silk screen printing of T-shirts. Mimeograph printing is also another form of porous (screen) printing.
screen rulings
The number of lines or dots per inch on a halftone screen. See also <i>screen</i>.
scuffing
The disrupted appearance of an ink film as a result of abrasion to either the wet or dry ink film.
scumming
A term describing the condition resulting when any non-image area of the plate tends to take ink (any cause); when this starts to occur in offset lithography, it is said that the plate is "catching up"; can also be called toning.
seam mark
Is a defect in the web, normally running at approximate right angles to the machine direction and is seen as a light streak when viewed by transmitted light. Point of origin is usually an article of machine clothing, a wire or a felt, that is seamed. The distance from one defect to the other is a clue as to the origin of the mark.
secondary fiber
A term used for wastepaper recycled into the paper making process.
semi-chemical
A pulping process, not widely used in Fine Papers, that uses chemicals to assist a mechanical pulping process, and gives a pulp similar to chemical pulp.
separation
The act of separating (dividing) the colors of an original into its component colors (yellow, magenta, cyan, black, and any spot colors); each record or negative is used for the production of a single color printing plate.
sequence
See color sequence.
set
Inks are said to be "set" when the ink film on a printed piece is immobile, though not fully dry, and can be handled without smudging/smearing.
set-off
Also called off-set; the transfer of ink from a printed sheet to another sheet in contact with it at the delivery end of a printing press and/or during subsequent bindery operations.
sewed
The actual sewing through all the pages of a book which is to be case bound.
shadow marks
1) Also couch marks; defects which appear as a regular pattern, always when viewed by transmitted light and sometimes when viewed by direct light. Cause is usually some non-uniform water removal from the sheet of paper in the wet end of the paper machine, and takes the pattern of the equipment removing the water (such as a drilled hole suction couch roll). 2) Can also be intentional watermark patterning, using the dandy roll. See also <i>dandy marks</i>.
sheet-fed printing
A printing process, where the paper is processed as sheets, as opposed to processing from a web (roll/ribbon). Ink-drying mechanisms can differ between the sheet-fed and web-fed offset lithography printing processes.
shives
Uncooked wood particles which show up in the finished sheet; in groundwood pulps. bundles of fibers resulting from less than mechanical separation.
short ink
See length.
show-through
Sometimes called strikethrough; the undesirable condition where the printing on the reverse side can be seen through the sheet under normal lighting. See also <i>opacity</i>.
shrunken edges
See tight edges.
side guide
A guide on sheet fed equipment to position the sheet sideways for the operation. On web fed equipment, this is called an edge guide.
signature
Folded sheet of printed paper usually a section of a book or magazine (or newspaper), ordinarily obtained by the folding of a single sheet into 4, 8, 16, or more pages. The term signature can also be applied to a printed flat sheet that is to be later folded into a multi-page document.
silk screen printing
A form of porous printing. Originally, the porous material for making the screen was a silk fabric, thus the name. See also <i>screen printing</i>.
simple curl
1) Structural curl is the bending of a sheet of paper around the grain direction. and is generally caused by differential moisture changes (cellulose fiber diameter changes) from one side of the sheet versus the other. 2) Wrap curl is the result of the sheet becoming "set" when wrapped around a core. It is always curled or bending perpendicular to the grain.
size
A water resisting material which is added to paper. See also <i>sizing</i>.
size press
The part of the paper machine that applies a surface size or treatment to the web of paper. See also <i>surface sizing</i>.
sizing
A treatment to improve the resistance to a liquid (particularly water) or vapor; surface or internal sizing; see size press, acid sizing or alkaline sizing. Sizing or waterproofness is generally measured as the time required for a water-based fluid or ink to penetrate from one surface of paper to the other, through the sheet.
skinning
The formation of a dried layer on the surface of a fluid such as an ink or coating (like a paint), after a period of standing.
slack sized
Refers to paper which has very little or no sizing, to resist moisture penetration; opposite of hard sized.
slice
The opening in the headbox of the paper machine, where the furnish is uniformly forced out onto the wire for the web of paper to be formed.
slime
Bacterial micro-organisms growing in the wet end of the paper machine system, that if left uncontrolled, can break loose and become a part of the paper web-usually a "slime" hole results. Normally controlled by slimicides or biocides, added to the wet end of the paper machine.
slimicides
See slime.
slip
High concentration slurry (even semi-solid) of paper making or coating pigment in water.
slipped roll
An unevenly wound roll which is usually the result of loose winding. See also <i>telescoped roll</i>.
slitter
A sharp knife (generally a sharp disc) which cuts paper into predetermined widths; if not properly set or maintained can give a poor, non-uniform, or dusty cut.
slitter dust
The accumulation of dust, primarily filler, fibers, or coating thrown off during the slitting operation, and remaining on or in the roll.
slush pulp
Cellulose fibers mixed with water so it can be pumped.
smashed blanket
An area of a blanket that is no longer firm and resilient, and that gives a light impression in the center of a well-printed area. Usually caused by physical damage of the blanket at impression.
smear
The spreading of ink, usually due to abrasion or rubbing of freshly (not yet set) printed ink to adjacent areas of the paper surface.
smoothness
The texture of the surface of paper; also called finish. Generally determined with an instrument which measures the flow of air along the surface of a paper sample under standardized loading and air pressure conditions, i.e., the greater or faster the flow/escape of air, the less smooth the surface.
smudge
The transfer of ink, usually due to abrasion or rubbing of a printed ink film, to an adjacent sheet or area (see smear) of the paper.
SNAP
Abbreviation for "Specifications for Non-heatset Advertising Printing"; a color proofing system to assure press to press, and run to run color constancy.
soda
A process and the product resulting from the pulping of wood, using a sodium hydroxide (lye) solution, under conditions of high temperature and pressure; see kraft for the more widely used alkaline pulping process.
softwood
Source of "longer" cellulose fibers for paper making, as extracted from coniferous or cone bearing trees.
soy oil
An agricultural product and renewable resource that is receiving increased usage in the manufacture of printing inks, as a replacement for a portion on the petrochemical based solvents and oils. Soy oils have many of the characteristics of petroleum based oils, but are not as easily evaporated as the lower molecular weight solvents, and are more compatible with water (with implications for fountain solution interactions).
spectrophotometer
An optical instrument to measure color or color differences from standard.
spectrum
The complete range of rainbow-like colors (continuous), generally in the visible range of wavelengths, from short/blue to long/red.
specular reflection
Light reflected from a surface at exactly the same angle as the incident angle of the light; as a mirror reflects an image.
spine
See backbone.
splice
Also called paster; the connection of a continuous web, such that later converting and printing operations can be performed satisfactorily. A splice is usually placed in the web during the winding process, when defective paper is removed or when material is added to complete a roll diameter or length. A web break, mis-register on the printing press, and damaged blankets due to excessive thickness are just three examples of a possible result of a "poor" splice. Also see butt splice; overlap splice is obvious.
spot color
Premixed, semi or fully opaque printing inks used for exact color match, as in a corporate logo (Examples: Coca Cola red or John Deere green). Used in place of trying to match exact colors by the combination of 3 or 4 process colors. Can also add visual impact and reduce the process ink costs.
squirt
The high-pressure water jet used on the wet end of a paper machine to cut the wet web to the correct width. Also, one jet is adjusted to cut a leader sheet or tail on the wet web as it is fed from the wire to the wet presses, and expands the web width once it is fed through the machine.
staggered winding
See offset winding.
standard illumination
The perceived color of paper and the color of the printed piece are greatly influenced by the illuminating light. For all visual color matching, there is a suggested/standard illuminating light.
starred end (roll)
Observed by the "star" pattern radiating from the core to the outer wraps of a roll, cause can be a soft end on the roll, tightly wound paper above paper that is loosely wound, or just from a severe impact.
start(s)
In the collation of signatures for a book, magazine or other publication, individual signatures may vary in moisture content, and after trimming, upon coming to equilibrium, give an uneven appearance to the edge of the printed matter. This is always after time. This nonuniform edge, with some signature or group of pages protruding more than an adjacent signature is called a start.
stiffness
Property of paper to resist bending.
stochastic screening
Conventional-screening technique gives fixed spacing (screen ruling) and variable sized dots for tonal value printing. Stochastic screening can give tonal values with both variable dot size/area and/or variably spaced dots. This is achieved by electronic media (computers) using digital imaging and laser exposure to achieve renderings approaching continuous tonal value photography, and no dot pattern. With no dot pattern, this eliminates undesirable rosette and moiré effects.
stone printing
See offset lithography.
stream feeder
A type of sheet feeding unit that allows several sheets of paper to lap each other to minimize the sudden acceleration or deceleration (start and stop) at the feed or delivery end of sheet fed equipment such as printing presses and sheeters.
strength
The strength of a sheet of paper is dependent primarily upon the nature and amount M) of fiber used to make the paper; the test to measure strength is dependent upon the characteristic to be measured, and can include such properties or measurements as surface strength, burst, tear, tensile, or other.
strike-through
See show-through.
stripping
1) In preparing lithographic plate making films, the placing of the negatives/positives in the proper place on the page. 2) As a defect in lithographic printing, describes the condition when the ink rollers take water preferentially to the ink (the ink roller surface changes from oleophilic to hydrophilic). Usually occurs on metal ink rollers, but can occur in synthetic composition covered rollers.
structural curl
See simple curl.
stuck web
Occurs when water, adhesive, coating or some other tacky material gets in between layers or wraps of a roll, causing them to adhere to each other.
substance weight
Synonymous with basis weight. Generally used with business papers measured on a 17" x 22" basic size.
subtractive primary colors
See primary colors.
sulfate
An alkaline process of cooking wood. See also <i>kraft</i>.
sulfite
A process and the product resulting from the pulping of wood using acid (as oppose to the pulping processes. See also <i>kraft</i> and <i>soda</i>.
supercalendering
The calendering method using alternate steel/metal and resilient (filled) rolls, generally to obtain various levels of gloss. See also <i>calendering</i>.
surface sizing
The surface application of material (generally in papermaking, a starch solution) to change its resistance to fluids; a cotton shirt or blouse may be surface sized from the laundry, i.e., it may have a starch application to give it "crispness" and resistance to moisture.
sweat rolls
See chill rolls.
SWOP
An abbreviation for "Specifications for Web Offset Publications", a color proofing system to assure press to press and run to run color constancy.
sword (hygroscope)
Sword shaped hygrometer that may be inserted into a pile of paper to determine its equilibrium moisture content, and for comparison with the surrounding air.
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