Fundamentals of Printing and Graphic Arts
This section covers Fundamentals of Printing and Graphic Arts, the domain that tests whether you can define printing as a reproduction system, distinguish the major processes and use graphic-arts vocabulary accurately.
Core rules and concepts
- Printing reproduces an image many times from an image carrier; the production chain is origination, prepress, press and post-press.
- Relief prints from raised areas (letterpress, flexography); planographic from treated flat surfaces (offset); intaglio from recessed cells (gravure); screen from stencil areas.
- Offset is indirect: plate to blanket to substrate. Gravure and flexography are direct.
- Continuous-tone originals are converted to halftone dots for most conventional presses; vector art suits type and logos, raster suits photographs.
- Process choice depends on run length, substrate, image quality, ink film and cost.
Worked example
A temple trust needs 300 invitation cards on 300 gsm card with four-colour images and gold foil. Reasoning: 300 is a short run, so digital toner or small offset avoids heavy plate set-up; foil is a separate post-press operation. For 3,00,000 cartons, sheetfed offset is more economical because plate cost is spread over the run. For plastic film packaging, flexography is preferred because flexible plates and fast-drying inks suit non-absorbent film.
Traps
Do not call offset a direct process; do not confuse screen printing with a digital screen display; do not treat DPI as a process measure; do not omit post-press when naming the production chain.