Printing Technique

Printing surface 

1. Intaglio (engraving) (음각) 

  - Carved or etched image on the metal plate → Surface wiped with ink to fill the recesses → paper contact under pressure 

  - Advantage: Suitable for large-format images (very fine detail)

  - Disadvantage: virtually impossible to print colours on the same sheet (half-tone), and to be reversed, printing plate gets degraded quickly, hand-engraving into copper is inappropriate to produce large copy.

 

2. Relief (letterpress)  (양각) 

  - Very common for text (developed from compositing individual letters to machines casting lines or pages in metal) 

  - Only simple line maps can be used: can't easily capture detail/colouring is not easy 

  - Relatively complex to produce 

 

3. Planographic - lithographic (평판) 

  - Image and non-image are on the same plane 

  - Common method of map printing is lithographic  

  - Drawing on the stone where the image was drawn on limestone using the chemical distinction 

  - Create a greasy surface which repelled water to separate into image and non-image damped with water → paper roll over applied ink (greasy ink attracted to image) 

  - Plate material: zinc →  aluminium & plastic / wrapped around cylinder 

  - Reprographic process: heliozincography(=photozincography) 사진아연철판술(凸版) 

Type of printing contact

1. Platen: contact flat surfaces, suitable for small format images 

2. Cylinder: printing surface is on a cylinder which passes over the paper between

3. Rotary : two cylinders rotate and paper passes between, normally at high speed

 

 

Offset printing

 

Images are firstly transferred to blanket (offset) cylinder made of rubber, which means smoothly indirect ink transfer to paper via blanket cylinder. Paper passes over between blanket and impression cylinder, therefore, plate become more durable, and paper gets less affected by damping.

Offset lithographic press is theoretically capable of 20,000 impressions (sheet) per hour (= 5-6,000 inch/ hr), but practically work 5,000 - 8,000 sheets per hr.

 

* Multi-colour litho printing: a series of offset printing with different colours. (Modern printing system) 

   - Microscope enables finer alignment along the printing devices.

   - Sheet or roll-fed (web-fed) printings are available

   - Very economical for large runs(생산량) but expensive if only small numbers required because of fixed set-up costs 

 

※ sheet-fed or roll-fed

* sheet-fed printing: high-quality printing process that individual sheets of paper fed into the printing machine mechanical registration to relate each sheet to one another to ensure that they are reproduced with the same imagery in the same position on every sheet running through the press 

* web-fed: rolls(webs) of paper supplied to the printing press, generally used for runs in excess of five or ten thousand impressions (e.g. newspaper and magazine)