The term “coloured edge” describes the finishing of paper edges with colour (also called edge painting) or with foil. Mechanical and manual methods can be applied.
All shades are possible, including neon colours. Other options are multi-colour, polychromatic and graded effects. Highly absorbent papers allow the ink to run into the paper to some extent, which makes it visible around the edges. Depending on the point of view, this is either seen as an imperfection or as an attractive effect.
To avoid this effect, working with hot foil is an alternative. This technique is also suitable for metallic colours. However, the colour range for non-metallic foils is limited. The foils can be “temperamental” when processed. Therefore, they should only be used in exceptional cases and, if possible, after an initial test run.
Coloured edges are suitable for all types of standard to thick cards. Letterhead paper, book blocks, notepads, etc. can be finished with this technique. However, thin papers below 170 g/m2 are less suitable for manual edge finishing with foil.
To create coloured edges, the pre-cut stack of paper is fastened with suitable clamps and inked as evenly as possible with a brush or a little sponge. Spraying is also possible. Poster, screen-printing or acrylic inks can be used for this technique. Coloured edge is also suitable for round edges, yet foil cannot be used for this purpose. Coloured edge is recommended if special colour mixes or effects are desirable. Please note that depending on the colour hue, ink coverage on darker papers can be insufficient.
For the manual creation of coloured edges with foil, the pre-cut stack of paper is smoothed out and subsequently coated with primer. The hot foil is applied and sealed with a hand roller with a heated silicone roll. Since the applied hot foil is very thin, the individual sheets of paper can be separated without difficulty. Only special hot foils are suitable for the mechanical creation of coloured edges with foil. Currently, they are only available in two shades of gold and one shade of silver. Coloured edge with foil is recommended for metallic colours or if it is not desirable that the paper absorbs any ink. The technique is also suitable for dark papers if ink coverage achieved by coloured edge is not sufficient.
All manual techniques for edge finishing can be applied from a print run of one print product. Mechanical finishing starts with a minimum print run of 100. The production time depends on the format and the thickness of the material. For thick cardboard and a print run of 5000, manual edge finishing can take several days. Film-laminated sheets can also be finished with colour or hot foil.
The current trend for coloured edge is to plan more courageous and colourful projects. Increasingly, experiments with folds on front and back covers are introduced. Since creating coloured edges with foil relies on the available hot foils, we do not expect to see any major changes in this segment.