Pancyprian TS Graphic Arts III Θ.Κ. flashcards

36 cards. Read the term and the definition here. The deck at the top of this page is optional.

Offset lithography principle

Planographic process where image and non-image areas are on the same plane; ink adheres to image areas while water keeps non-image areas ink-free, then transferred via blanket to substrate.

Anilox roller

In flexography, a engraved roller with cells that meter a controlled volume of low-viscosity ink onto the plate; cell count and depth determine ink film thickness.

Gravure doctor blade

A steel blade that scrapes excess ink from the gravure cylinder surface, leaving ink only in engraved cells; blade angle and pressure affect cell emptying and print density.

Screen printing squeegee

A rubber or polyurethane blade that forces ink through the mesh stencil; hardness, angle, and pressure control ink deposit and edge sharpness.

AM screening

Amplitude-modulated halftone where dot size varies at fixed screen frequency and angle; common screen rulings are 150–200 lpi for offset; angle sets avoid moiré.

FM screening

Frequency-modulated (stochastic) halftone where dot size is fixed and small while dot frequency varies; reduces moiré and improves detail but requires tighter process control.

Total area coverage (TAC)

Sum of CMYK dot percentages at a given point; typically limited to 300–340% for coated stock and lower for uncoated to prevent set-off and drying problems.

RIP

Raster image processor converts page description (PDF/PostScript) into a raster at output device resolution; applies screening, trapping, and colour conversion before imaging.

CTP

Computer-to-plate imaging exposes plates directly by laser, eliminating film; plate type must match imager wavelength (e.g., thermal 830 nm, violet 405 nm).

Imposition

Arrangement of pages on a press sheet so that after printing, folding, and trimming the pages appear in correct reading order; pages per sheet = sides × rows × columns.

Trapping

Slight overlap (spread or choke) of adjacent colours to compensate for misregistration on press; typical trap width 0.1–0.2 mm depending on process and substrate.

PDF/X-4

ISO standard for print-ready PDF supporting live transparency and ICC colour management; unlike PDF/X-1a, it does not require flattening.

Additive colour

Colour model where light primaries red, green, and blue combine to produce white; used in displays and scanners; device-dependent without profiling.

Subtractive colour

Colour model where cyan, magenta, and yellow inks absorb light; combining all three ideally yields black, but practical inks require added black (K) for density.

ICC profile

A file characterising a device's colour response, enabling conversion between device-dependent colour spaces; source and destination profiles plus rendering intent govern output.

Rendering intent

ICC conversion strategy: perceptual compresses gamut, relative colorimetric preserves in-gamut colours with white point adaptation, absolute preserves exact colorimetry, saturation favours vividness.

Densitometry

Measurement of optical density of ink films; used to control solid ink density (SID) and dot gain on press; densitometers use filters matched to process colours.

Delta E (ΔE)

Numerical colour difference between two measured samples in a uniform colour space (e.g., CIELAB); ΔE00 below about 2 is often visually acceptable in print.

Spot colour

A pre-mixed ink printed as an additional separation, often from a matching system such as Pantone; extends gamut and ensures brand colour consistency.

Point and pica

Typography units: 1 point = 1/72 inch (approximately 0.3528 mm); 12 points = 1 pica; used for type size, leading, and rule thickness.

Leading

Baseline-to-baseline distance between lines of type, usually expressed as type size/leading (e.g., 10/12); affects readability and text block colour.

Kerning

Adjustment of spacing between specific pairs of characters to achieve optically even spacing; distinct from tracking, which adjusts spacing across a range of characters.

Baseline grid

A layout grid of evenly spaced horizontal lines to which text baselines align across columns; maintains vertical rhythm and consistent leading.

Widow and orphan

Typographic faults: an orphan is a single line at the top of a page or column; a widow is a single line at the bottom; avoided by copyfitting or spacing adjustments.

Grammage

Mass per unit area of paper or board, expressed in grams per square metre (g/m² or gsm); determines weight, bulk, and suitability for a job.

Paper grain direction

Direction of fibres in paper; folding parallel to grain reduces cracking; grain affects dimensional stability and registration; determined by tear or fold test.

Oxidative drying

Ink drying mechanism where oils in the ink absorb oxygen and polymerise; typical of lithographic paste inks; can be accelerated by driers and heat.

UV curing

Instant drying of UV-curable inks or varnishes by exposure to ultraviolet radiation; enables high gloss and immediate further processing.

Saddle stitching

Binding method where wire staples are driven through the fold of gathered sections; suitable for booklets typically up to about 64 pages depending on paper weight.

Die-cutting

Cutting and creasing of printed sheets using a steel-rule die; make-ready involves packing to equalise cutting pressure across the forme.

Perfect binding

Binding where gathered sections have their spines trimmed and glued into a cover; used for books and catalogues; page count and paper grain affect strength.

Safety data sheet (SDS)

Document providing hazard, handling, and emergency information for chemicals such as inks, solvents, and developers; must be accessible in the workshop.

Machine guarding

Physical barriers and interlocks that prevent access to nip points, gears, and rotating parts; guards must not be bypassed and require lockout for maintenance.

Waste allowance

Additional sheets added to a print run to cover make-ready, spoilage, and finishing losses; gross sheets = net sheets × (1 + waste percentage).

Break-even quantity

Run length at which total costs of two processes are equal; calculated as (fixed cost A − fixed cost B) / (variable cost B − variable cost A).

Ream weight

Mass of a defined number of sheets (traditionally 500); calculated from sheet area, grammage, and sheet count; used for paper ordering and costing.