Have you ever been interested in how to make a printed product more attractive or how to prolong its durability? Printed products are varnished during or after printing to protect them from scratching and to enhance the look.

More beautiful and resistant printed pieces

There are two most important functions of varnishing in printing industry.

The aesthetic function – the colours get more saturated and unified. Varnished products get better appearance. Metalling or scent varnish is used to add luxury and elegance to the products. Sometimes, varnish is applied to limited areas of the printed product. This is call partial or spot varnish and it makes the selected areas visually pop out.

The protective function – varnish protects the product from fingerprint, scuff, blurring and colour changes. Larger printed products with saturated colours tend to be damaged more easily. Besides, varnish protects printed products from moisture, fat or UV light and prolongs the duration.

There are several types of printing vanish – matte, glossy, scuff resistant, colourful, metalling or scented. These types of varnish, which are also called oil varnish, have similar composition to print inks. They are applied from colour store unit, and they dry by air oxidation. The advantages are easy application, good absorption in paper and flexibility of varnished layer. Longer drying time, low gloss (60 to 65 points), worse protective properties and yellowing of the film are disadvantages of printing varnish. Printing varnish must not be used for food packaging. When using printing varnish it is not necessary to prepare specific printing data.

Dispersion varnish needs thicker paper

These varnishes are water based, contain water soluble resin, polymer dispersions and additives. They include glossy, matte, colourful, metallic, thermal, scented, blisters and primers. Dispersion varnishes can be applied using an individual varnishing unit of a printing machine or using a colour store box. In the case of the latter one, they must be modified. Drying is achieved using hot air or UV light. Excessive water evaporates from the varnish.

The advantages are that the gloss level is higher compared to printing varnishes (80 to 85 points). It dries quickly, which makes the production process faster and the varnish does not go yellow. Dispersion varnishes are applied in thin layers, which results in some disadvantages, e.g., orange peel or varnish cracking. As they contain water, they are not suitable for thin papers, which may curl subsequently.

Dispersion varnishes are not scented so they can be used for food packages. They can be applied over the whole printed area or partially. It is not necessary to prepare any specific printing data before the application.

UV varnishes for maximal gloss

UV varnishes contain photoinitiators which react to UV light. As they are aggressive to the environment, printing machines with modified colour store box must be used for their application. After varnishing, the printing product is exposed to UV light which causes instant drying and stiffening. Maximal gloss can be reached (90 to 95 points). The colour must be dry, otherwise the varnish may change in shade. Sticky surface, cracking of the surface, imperfect stiffening in depth or higher price are disadvantages of UV varnishes.

On the other hand, quick drying process, possibility to apply thicker layer, water and dust resistance and longer durability are the advantages of UV varnishing. Other benefits are that printed products keep the colour, are sunlight resistant and the gloss is 40 percent higher compared to printing varnish. UV varnishes do not contain organic solvents which means they are environmentally friendly, and the printing products are fully recyclable.

When the printed product is overcoated, it can be considered a cheaper substitute for lamination. UV varnishes are also used to cover just selected sections of the surface. Besides matte, glossy or scented varnishes, there are varnishes with special effects, e.g., water drops, crocodile skin etc.

Special varnishes make the printed matter original

  • Hybrid drop off varnish – a varnish with high gloss which is applied on a matte film. On areas which need to be glossy, matte varnish is not used. On the remaining areas, the two varnishes react and create smooth matte surface.
  • Orange peel (hybrid varnish) – it uses the same principle as drip off varnish. Two varnishes react and create surface reminding of orange peel.
  • Glitter varnish – creates sparkle effect. It is available in various shades including silver or gold shade.
  • Pearly varnish – contains iriodin, which is a high gloss pigment. It is available in silver, gold, bronze and copper shade. Some types create a rainbow effect.
  • Fluorescent varnish – shines in the dark.
  • Card varnish – the surface has lower friction, so the sliding effect is high.
  • Wiping varnish – is applied under wiping colour (seriography).
  • Varnish for hot stamping – high-gloss varnish used for hot stamping, glue application or cold foil (seriography, thermography)
  • Elastic varnish – due to good elasticity and adhesiveness is applied to semi-solid and self-adhesive vinyl products.
  • Glossy anti-slip varnish – creates non-slip surface with high friction. It is applied to mouse pads.
  • Satin anti-slip varnish – creates non-slip resistant surface and is applied to non-slip floor stickers.
  • UV adhesive varnish – Thin layer can be easily removed. Thicker layer guarantees strong adhesivity.
  • Luminescent varnish – can only be seen under UV light and is applied to protection elements.
  • Self-touch varnish – water-based varnish, hardened with UV light. Its advantages are good adhesiveness, matte appearance in any thickness and high abrasion resistance. Can be used to hot stamping. Requires stronger UV light, otherwise it takes longer to harden.
  • Write and erase varnish – creates surface ready to write on with a pen, pencil, or chalk. It is water-based, and it is hardened with UV light.
  • Varnish with gross structure – creates structure similar to sand.
  • Structure varnish for Brail – is used in thick layers, is flexible and suitable for both rotation and flat printing. It is UV varnish.
  • Washable varnish – UV varnish. It is possible to write with markers on the surface coated with washable varnish and wipe the text.
  • Non-absorbing varnish – UV varnish applied to paper.
  • COIN scratch off varnish – creates an invisible image, which can be revealed after rubbing the surface with a coin. It is not possible to scan or copy the surface.
  • Stamping varnish – absorbs stamping ink and lets it dry quickly – printed product coated with this type of varnish can be stamped.

Conclusion

  • printing varnish comprise the basic set. They provide the printed material with basic protection and low gloss. On the other hand, they are cheap and easy to apply.
  • Dispersive varnishes provide the printed product with better gloss and protection compared to printing varnish.
  • UV varnishes give the product maximal gloss and protection, they harden quickly, considerably prolong the durability of the product and are environmentally friendly. They require modified printing machines.
  • To reach special aesthetic effects or forgery protection, special varnishes can be used.