Metallic Inks are inks containing a mixture of ink (usually unpigmented) and metal dust or flakes, resulting in a shiny appearance. Most people love the look a metallic ink gives to a printed piece, especially when the image lends itself to the technique (think automotive or industrial). Whatever the subject may be, if you are planning on using a metallic ink on your next print project here a couple things to keep in mind.
• Metallic inks must be mixed as close to press time as possible. Printing with them takes longer because a metallic generally requires two passes on press – even paper stock with good ink holdout might need to coats of metallic ink to give you the results you’re looking for in large solids areas.
• There are two types of metallic inks: leafing and on-leafing. Leafing inks require tiny particles to float to the surface of the resin creating the metallic effect – so make sure to allow for ample drying time. Non-leafing metallics contain metal flakes that sink down into the resin and require varnishing.
• Most metallics tend to tarnish, fingerprint and scuff so a non-glare varnish or aqueous is a good idea. Take special care when varnishing a metallic, especially with UV or water based coatings. The typical approach is a dull varnish applied in-line as an additional color. Beware, varnishing a metallic does not make it shinier – actually it can lose some of its luster.
• Metallics can cause problems if you’re printing digitally, flakes from the metallic ink can build up on the fuser rollers. Also take care if printing metallics in-line with other colors, this can be problematic due to their chemistry and opacity. It’s a good idea to print them in separate pass if they trap to other colors.
• As with any special technique, it’s a good idea to talk to your printer first. Plan to adjust your schedule and budget accordingly. If the cost of printing a metallic + varnish or underlay of opaque ink is cost prohibitive, you might consider foil stamping or selecting a match color that approximates a metallic.
• Metallic inks look best when printed on a coated sheet –make sure you keep this in mind when specifying the paper for your job. They can be used on uncoated but will not give the same effect – with leafing metallics, the uncoated paper will absorb the resin and the flecks will rise to the surface giving it a mottled effect, almost like mercury glass. Finch put out a great piece last year, Think Ink, which perfectly illustrated this.
• Use coarser screen for halftones to prevent plugging, metallics lose luster with a low screen values. Avoid designs that require trapping a metallic against a process ink and don’t overprint a process ink over a metallic (it will look grayish).
• When proofing pay close attention to registration, and view the piece in different lighting conditions as well as the viewing area.
To request more information on metallic inks or to see print samples featuring metallics, contact our sample department.