Prepress

Graphic Design and Reproduction

The design that determines how a pack looks covers decisions on dimensions, format, colour, typography and imagery. Reproduction is the process of making that design ready for printing: colours are separated, resolution and dimensions are checked, and seal and cut areas are marked on the artwork.

At this stage, colour matching is tested and the design’s outcome under real print conditions is predicted. Well-prepared reproduction prevents colour and registration problems from the outset.

GMG Contract Proof

A GMG contract proof is a reference print produced before printing that shows the colour target. Together with customer approval, it gives the press operator a measurable point of comparison, so the colour achieved on press can be compared directly with the approved proof.

Cylinder Engraving

In rotogravure printing, the design is engraved onto the surface of a metal cylinder. A separate cylinder is prepared for each colour. The process generally consists of three steps:

• Preparation: The colour-separated artwork file is transferred to the engraving system.
• Engraving: Cells corresponding to the tones of the image are engraved into the copper-plated cylinder surface.
• Plating: The surface is chrome-plated so it can withstand wear during printing.

Correctly engraved cylinders ensure consistent results over long print runs.

Ink Preparation

The ink used for printing is prepared according to the film type, print speed and end-use conditions. Pigments, binders, solvents and additives are mixed in set proportions, and colour shade, viscosity, drying speed and adhesion values are adjusted.

Homogeneously mixed, correctly adjusted ink helps keep the colour the same throughout the print run.