Printing Brian Russell

Exam expectations Paper/card is the compulsory material so always expect questions in exam to relate to this topic. Questions on printing usually link to packaging.

What do you need to know? At the very least you should be able to name a commercial printing process and explain why it would be chosen It also links to other manufacturing questions

Commercial manufacturing Typical order of work: Finishing – print, varnish, emboss… Wastage/separation – die-cut/crease Forming - folding Assembling – glue, inserts… This order is different from many manufacturing processes

Commercial Manufacturing Typical litho presses set up for 4 process colours, a spot colour and varnish in one continuous cycle Typical folding machine for small cartons

Commercial Manufacturing Typical rotogravure printing presses set up for 4 process colours, metallic spot colours and varnish in one continuous cycle Typical flexographic press used for printing plastic film

Printing card Typically offset lithographic or gravure process used 4 process colours – yellow, magenta, cyan, black Varnishing, foil blocking, embossing are common

Offset lithography Flat aluminium plates (specially treated) Photographically exposed then wrapped around roller Exposed parts attract water Non exposed parts allow ink to stick Print onto plain roller to reverse image Transfers to card or other materials

Gravure Printing Used for very large print runs Uses engraved plates Ink is held in recesses known as cells Paper is pressed onto plate and ink is lifted from cells

Rotogravure Presses Cylinders are placed in line with a heater between each one to dry the ink

Flexographic printing Uses a printing plate made of rubber, plastic, or some other flexible material. Ink is applied to a raised image on the plate, which transfers the image to the printing

Printing terms Process colours – yellow, magenta and cyan make full range of colours, black adds definition (and text) Spot colours – mixed to exact colour Web offset – printed onto a roll (e.g. newspapers) Plate – has the image on, wraps around a cylinder Offset cylinder (or blanket cylinder) – reverses image Impression cylinder – presses paper onto plate Varnish – adds shine (or could apply a matt finish) to print, sometimes in isolated areas Substrate – material to be printed e.g. paper

Other related processes Die-cutting is the method most paper/card shapes are cut out. In the packaging industry the cutter is known as a cutting forme. Foil blocking is a method of applying a very thin layer of metal foil onto the surface to add a special effect Embossing is the method where the surface of the card is pressed upwards to create a special effect

A few exam tips Offset lithography is the best answer for any questions relating to the printing of card packaging Flexography is the best answer for any question relating to the printing of plastic film (such as carrier bags) Printing is a finishing technique suitable for card and some other materials