According to their industrial classification, varnishes can have a significant impact on printed papers and packaging. Its application on paper is similar to ink in that it helps to enhance the visual appearance of print or packaging as it passes through the printing press.
Gloss: Produces a smooth surface; the process typically applies a gloss over an entire surface area or specific areas. It creates contrast while adding depth to color and detail. But it also results in reflective surfaces that can interfere with the readability of text.
Matte: Matte varnishes create a smooth finish and a soft, subtle look. As a non-reflective surface, it makes text easy to read. If you're looking for a dynamic effect, it's better to stick with gloss. However, this type of coating may have multiple effects. In addition, like spot UV coatings, matte varnishes can be dispensed with high precision.
Satin: A combination of matt and gloss varnishes, Satin varnishes strike a balance between medium gloss and high abrasion resistance. The effect of satin varnish lends a subtle beauty. It almost looks like there is no protective coating on the print media.
Strike-through matte: Strike-through refers to the technique of applying both matte and gloss varnishes on the same print area. The matt varnish is first applied to all areas of the coated panel except those where a glossy effect is desired.
A high-gloss AQ coat covers the entire sheet, allowing the matt varnish to "break through" to the surface and allowing the glossy areas to shine. The purpose is to create a visual distinction between different areas of the printed sheet.
The varnish improves the perceived quality of the product. It's also an economical and user-friendly process that can be easily applied by adding spot finishing or other processes throughout the sheet. It can be manipulated to get the desired result.
However, it offers a lower degree of protection than water-based and UV coatings. They are also prone to yellowing over time. Varnishes are also not particularly environmentally friendly and need to be applied carefully to prevent the release of toxic compounds into the atmosphere.
Instead of a single process to produce varnish prints, there are different methods to achieve different results. For example, in wet trapping, varnish applies wet ink in-line for efficient registration. In contrast, dry trapping involves drying the ink and passing it through the press twice to print the varnish.