The Print process

Lithography is used to produce posters, books, newspapers, and packaging — just about any smooth, mass-produced item with print and graphics on it. The large majority of print produced at Gpex including books, posters, leaflets, stationery, folders and more are printed using one of our Heidelberg offset lithographic presses.

How it works

Before printing can commence we convert your artwork into a printable image. This is done using our PDF workflow system which enables us to transfer your work to a printing plate, you can read more about this later.

In our factory flexible aluminium printing plates are used. Modern printing plates have a brushed or roughened texture and are covered with a photosensitive emulsion. The image on the plate is created through direct laser imaging in our Kodak CTP (Computer-To-Plate) platesetter.

The positive image is the emulsion that remains after imaging. For many years, chemicals have been used to remove the non-image emulsion, but now Gpex utilise non-process plates that do not require chemical processing therefore keeping our print more environmentally friendly.

How the lithographic printing press works

The aluminium plate is affixed to a cylinder on a printing press. Dampening rollers apply water, which covers the blank portions of the plate but is repelled by the emulsion of the image area. Ink, which is hydrophobic, is then applied by the inking rollers, which is repelled by the water and only adheres to the emulsion of the image area to be printed.
If this image were directly transferred to paper, it would create a mirror image and the paper would become too wet. Instead, the plate rolls against a cylinder covered with a rubber blanket, which squeezes away the water, picks up the ink and transfers it to the paper with uniform pressure. The paper rolls across the blanket drum and the image is transferred to the paper. Because the image is first transferred, or offset to the rubber drum, this reproduction method is known as offset lithography or offset printing.

Many innovations and technical refinements have been made in printing processes and presses over the years, including the development of presses with multiple colour units. Our lithographic presses each contain five units enabling us to print five colours in one pass. This means that full colour, which is made up of the four primary process colours, cyan, magenta, yellow and black can all be printed in a single pass.

In order to achieve the optimum quality, all lithographic presses must first undergo a process called ‘make-ready ‘. This means that the colour must be brought up to strength, measured for accuracy and registration before the print run commences.

Digital printing uses techniques that were originally developed for computer printers.

The process of digital print differs from lithography printing in several ways. With digital print every print can be different, because printing plates are not required. There is also less waste chemical and paper, because there is no need to make-ready as this is managed automatically by the digital press.

One of the key differences between digital and lithographic printing is the way ink is used.With digital printing the ink or toner isn’t absorbed by the paper, as it is in conventional printing, instead forming a thin layer on the surface. This can result in a slightly different texture especially when printing on uncoated paper. Because there is less initial setup and no printing plates, it is useful for short run fast turnaround printing, proofing, and extremely cost effective for short print runs.

Our digital printing presses also have the benefit of in-line finishing for booklets and stitching options making it even quicker to produce a finished product.

Digital Printing is also used for personalised printing, or variable-data printing (VDP).

Display Printing

Display Printing covers short run large format digital printing that is usually produced for interior or exterior display.
We are able to produce a variety of work using our large format, flatbed or direct to substrate printing equipment.
Display Printing can be used for a number of applications, from simple advertising posters to multiple panel pop-up graphic systems used for exhibitions or events.

New technology allows us to print on a large variety of substrates including canvas, polyester, vinyl, PVC, Foamex, acrylic and aluminium. This provides a huge variety of ways to communicate your brand or message effectively. The digital process coupled with rapid drying times allows very quick turnaround.

Large format digital printing machines now offer excellent image quality similar to that of the more conventional methods.