Pancyprian TS Graphic Arts III Θ.Κ. key terms

A printing process in which ink is transferred from a plate to a rubber blanket and then to the substrate, based on the repulsion of oil-based ink by water on the non-image areas.

A rotary relief printing process using flexible photopolymer plates and low-viscosity fluid inks, widely used for packaging films, labels, corrugated board and newspapers.

An intaglio process in which the image is engraved into a copper-plated cylinder as cells of varying depth; ink fills the cells and is doctored off the surface before transfer to the substrate.

A stencil process in which ink is forced through open areas of a mesh screen onto the substrate using a squeegee, producing thick ink films on almost any material.

The cylinder on an offset press that carries the rubber blanket; it receives ink from the plate cylinder and transfers it to the substrate under pressure.

A ceramic-coated, laser-engraved roller in flexographic presses whose cells meter a precise, uniform film of ink onto the printing plate.

A water-based mixture of fountain solution and alcohol or substitute that wets the non-image areas of an offset plate so they reject ink.

A relief printing plate made of a light-sensitive polymer that is exposed through a negative, washed out and dried to leave raised image areas.

A prepress workflow in which a digital file is imaged directly onto a printing plate by laser, eliminating film and the contact exposure step.

Software that converts page description or PDF data into a high-resolution bitmap of dots that an output device such as a platesetter or digital press can image.

The arrangement of individual pages on a large press sheet so that, after printing, folding and trimming, the pages fall in the correct reading sequence.

The process of converting a full-colour image into the separate cyan, magenta, yellow and black (plus spot) components that will be printed as individual plates.

The reproduction technique that converts continuous-tone images into variable-sized dots at a fixed screen ruling, creating the illusion of tonal gradation.

The number of halftone cells or lines per unit length, usually expressed in lines per inch or lines per centimetre; finer rulings reproduce more detail.

A separation technique that replaces part of the cyan, magenta and yellow ink in neutral shadow areas with black ink, reducing total ink coverage and improving grey stability.

A separation method that substitutes black ink for the neutral grey portion of a colour throughout the tonal range, lowering ink consumption and improving register tolerance.

The combination of red, green and blue light, as on a monitor or scanner, where adding light increases brightness and all three together produce white.

The combination of cyan, magenta and yellow colorants, each of which absorbs part of the spectrum; together they remove light and approach black.

The four process inks used in colour printing: cyan, magenta, yellow and black, printed as overlapping screened images to create the full colour range.

A pre-mixed ink printed from its own dedicated plate rather than built from process colours, used for brand colours, metallics or colours outside the CMYK gamut.

A standard data file describing how a specific device reproduces colour, allowing a colour management system to convert colours accurately between devices.

A setting that determines how out-of-gamut colours are mapped when converting between colour spaces, such as perceptual, relative colorimetric, absolute colorimetric or saturation.

The measurement of the optical density of printed ink films or films, used to monitor ink laydown and consistency on press.

The increase in apparent halftone dot size from prepress file to printed sheet, caused by ink spread, pressure and substrate absorbency; it darkens midtones.

The sum of the CMYK dot percentages at a given point, which must be limited to avoid set-off, slow drying and poor trapping on high-speed presses.

The grouping of typefaces by historical and structural features, commonly into serif, sans serif, slab serif, script and display categories.

The typographic measurement system in which 1 point equals approximately 0.353 mm and 12 points make one pica, used for type sizes and spacing.

The vertical distance from baseline to baseline of successive lines of type, traditionally set in points and usually larger than the type size for readability.

A layout grid of evenly spaced horizontal lines to which the baselines of all text sit, ensuring consistent vertical rhythm across columns and pages.

The mass of paper expressed in grams per square metre (gsm), the standard measure of paper weight and a key factor in press and post-press settings.

The thickness of a sheet of paper or board, usually measured in micrometres or thousandths of an inch, affecting stiffness, bulk and foldability.

Paper whose surface has been treated with a mineral coating such as clay or calcium carbonate to improve smoothness, gloss and ink holdout.

The ability of a substrate to keep ink on its surface rather than absorbing it, which governs gloss, dot sharpness and colour density.

A curing mechanism in which offset inks absorb oxygen and cross-link to form a solid film; it is accelerated by driers and can be slowed by acidic dampening solution.

Instant hardening of inks or varnishes by ultraviolet light or electron beam, allowing immediate further processing without spray powder.

A folded press sheet containing a group of pages in multiples of four that, when gathered and bound, forms part of a book.

A binding method in which the folded edges of gathered signatures are trimmed off and glued into a flexible cover, typical of paperback books and magazines.

A binding method in which folded signatures are nested and stapled through the spine fold, used for slim booklets and brochures.

A finishing operation in which a steel rule die is pressed through the substrate to cut a shaped outline or to crease fold lines.

The precise alignment of successive printed colours, plates or finishing operations on the same sheet; misregistration produces visible colour fringes.

A document supplied with a hazardous substance that lists its hazards, composition, handling precautions, first-aid measures and disposal requirements.

Organic solvents that evaporate from inks, washes and adhesives, contributing to air pollution and requiring extraction and control in the workshop.

Physical barriers, interlocks and light curtains fitted to presses, guillotines and folders to prevent operators reaching dangerous moving parts.

A procedure for isolating and securing energy sources before maintenance or clearing a jam, ensuring machinery cannot restart while a person is inside it.

The priority order for managing waste: prevent, reuse, recycle, recover energy, then dispose, applied to paper trim, plates, inks and solvents.

The number of individual images printed across the width of a press sheet, determined by the imposition scheme and sheet size.

The extra sheets added to a print run to cover make-ready, spoilage, register waste and finishing losses, usually expressed as a percentage of the net quantity.

The preparatory work before a production run, including plate mounting, register, ink and dampening adjustment, which consumes sheets that become waste.