Laminating a wide format digital print comes as one of the final steps in wide format digital print production.

When we decide to laminate a print, we usually consider four main reasons: effect, protection, application, and durability.

The finish of the laminate enhances the print image. Choosing which finish often comes down to a matter of personal preference.

Gloss laminates increase the saturation and depth of colours as well as improving image contrast. Gloss tends to work well as the preferred finish for outdoor signs and vehicle graphics.

Matt finishes soften colours and contrast. As matt is non-reflective, it makes a good finishing solution for hiding imperfections and increasing the legibility of text in brightly lit interior environments.

Satin and lustre laminates deliver an in-between effect, providing not only good colour and contrast but also glare reduction.

Nowadays, we also have laminates that completely change the look of the image. Structured and embossed laminates can be applied onto prints to make them look like leather, carbon fibre, crystal, ice, peach skin, metal, or wood. The effects that these films create open up a whole world of possibilities in the interior design market, offering digital images that look like authentic interior finishes.

Protecting prints

USING a laminate protects the image from scratching, chemicals and other contaminants. Laminating also makes prints easier to clean without affecting the print. Lamination can add functionality to a graphic by protecting it from graffiti or providing a non- slip surface for floor graphics.Laminating a print will also impact on the installation of the graphic.

From a positive perspective, laminating can give a print more rigidity which makes application easier. It can, however, also affect the performance of the underlying film especially for applications requiring conforming of the graphic onto a 3D surface. The laminate can reduce the conformability and increase tension in the film construction.

When applying a laminated graphic, the adhesive on the print film must have enough strength to hold the two layers of film in place even when it wants to move. If the adhesive does not have sufficient strength, the applicator will need to cut the film when applying it into deep recesses to release the tension.

Polyester laminates will completely reduce a film’s capacity to conform and you should only use them on flat surfaces. When choosing a laminate, you need evaluate its compatibly with the type of surface shape to which you will apply it.

One of the main reasons that we choose lamination is to protect the print from what can be the harmful effects of UV.

UV breaks down the chemical bonds present in the ink which presents itself visually as colour fade.

UV inhibitors present in the laminate can prolong the durability and colour intensity of the inks. Today, we have access to inks that have greater durability and UV resistance so laminating to increase the life of the ink is not always necessary for short term or indoor campaigns.

Smart choices

THE rules for choosing laminates are simple: use like products with like products. Use monomerics with monomerics; use polymerics with polymerics; and so on.

There are exceptions of course. You can use polyesters to laminate PVCs. The reason for recommending compatible constructions is that different films expand and shrink at different rates.

With a laminated print, the adhesive of the laminate is a fluid layer which allows for movement. If the laminate and base film move at different rates you can get problems like delamination or tunnelling.

If you must mix grades of print film and laminate, the higher quality laminate should always go on top. For example, laminating a monomeric print with a polymeric laminate is less risky than laminating a polymeric print with a monomeric laminate. This is due to polymeric laminates, in general, being more stable and having less shrinkage.

If the film with the higher shrinkage is used as the laminate, it will pull on the underlying film which can lead to lifting. While you can mix and match between brands, if you have an issue with the graphics performance, it does make testing and evaluation more challenging, as well as the process of determining which brand caused the failure.

Also, some manufacturers will void warranties if their products are combined with other brands. For this reason, the ideal solution is to use the same brand of product and follow the supplier’s recommendations. This will ensure compatibility and safeguard any film warranties.

Quality matters

THE next key to successful laminating involves the use of the correct product.

All laminates are not created equally. The label of monomeric, polymeric and cast is not the sole determinant of the performance or the aesthetic finish of the laminate.

Appearance, durability, UV protection and resistance, silvering and colour deepness are all influenced by the quality of film, adhesive, ingredients used and expertise of the manufacturer.

The label of polymeric and monomeric simply references the type of plasticiser used to soften the PVC. As such it is just one component of many and is never the sole determinant of the films overall performance. This is the same with cast and calendared labels which merely describes how the film was produced. It always pays to delve further and refer to the technical data sheets to see what performance parameters are actually being offered.

It is also wise to check that the laminate you plan to use is compatible with the ink type.

Prints using UV ink can benefit by using a laminate that has an adhesive specifically designed for this application. Because UV ink cures instantly it is not smooth. In order to get a nice finish and good anchorage to the print once laminated the adhesive needs to flow across the uneven surface and fill the peaks and troughs. As such, the fluidity and coating weight of adhesive needs to be sufficient for this to happen. If it is not so, you can have problems with delamination or a silvering appearance.

Even after choosing the right film combination things can still go wrong.

If you are getting issues like bubbling, silvering wrinkling, orange peel, waving, blistering, print curl, static electricity or other distortions and the films you are using are matched and compatible then the likely cause will be related to setup and processing. The solution can be as easy as adjusting the laminator settings and your production procedures. There are many guides and industry experts who can help with these issues.

Lamination films make a great value add for print producers. By selecting the right products, you can use lamination to enhance the aesthetic, durability and functionality of any graphic installation.

Comment below to have your say on this story.

If you have a news story or tip-off, get in touch at editorial@sprinter.com.au.  

Sign up to the Sprinter newsletter