Generally most commercial printing is done by offset process which involves single colour, spot colours or process colours. Digital printing is also used for smaller printing quantities.
Single colour is the cheapest form of printing and is widely used to print bulk flyers, business cards & invoice books, where cost is a concern when promoting your product.
Spot colours are mainly used in business stationery example letterheads, compliment slips, business cards & envelopes where colour uniformity is vital for the corporate identity. The colour coding follows a Pantone Matching System (PMS) providing thousands of different specific shades. Process colour is a 4 colour offset process utilizing the 4 basic colours: cyan, magenta, yellow & black (CMYK). Bulk printing with this method is very cost effective e.g. colour flyers, booklets, magazines, business cards etc.
What is offset printing?
Offset printing is a term used referring to the printing process by which ink is transferred (offset) from a plate to a rubber blanket and then to the printing paper. This technique is based on the lithographic process concept oil & water does not mix. The non-image area on a printing plate attracts water & remains damp and the water is expelled from the image areas.
Thus ink from the ink rollers is only transferred to the image areas of the plate, so the ink, being oil based, is not retained by the dampened areas of the plate. The ink and water balance ratio is very important in producing high quality printed jobs.
Most of the printed material nowadays is done by Lithographic Offset Process and is very cost effective in high volume work.
Another modern printing method is Digital Printing (laser or ink jets) which produces high quality printing but at a greater cost. This process does not require much initial setting up and is best suited for large posters and smaller quantities where by comparison offset printing will cost more per unit because of the setting up costs.
There are basically 3 stages in the print production.
- Bindery or finishing.
The pre-press which includes Graphic Design, involves artwork concepts to finished art work. Photo-lithography process to make negatives from artwork, the negative image is then burned in to the offset litho plates. Nowadays, this stage has been eliminated by the use of Direct Image to plate technology.
The second step is the actual print production on offset printing presses or digital printing machines.
The last stage is the finishing which may involve collating, folding, stitching (stapling), binding, cutting (trimming) and packaging for dispatch.