Putting ink to paper is fundamental to the print production of pressure sensitive labels (PSL). Inks add colour, tone and even texture to a design. Standard printing uses the four process colour inks cyan (C), magenta (M), yellow (Y) and black/key (K). K stands for key as the cyan, magenta and yellow printing plates are aligned with the key of the black plate. Dots of each of the four colours are layered on top of one another to simulate a full spectrum of colours.
Lebone Paarl Labels’ MPS UV flexo self-adhesive presses use rapidly drying ultraviolet (UV) curable ink – each colour is rapidly dried by UV drying lamps before the next colour is added. This allows for high printing speeds and eliminates heat. There are also no harmful emissions.
UV flexo inks used for label printing boast high colour strength and print sharper, finer dots to achieve superior print quality and more intense colours than solvent- or water-based flexo inks. They also offer outstanding chemical and physical resistance properties.
“Each of our presses is set up with eight or nine colour stations to enable the cost and time efficient inclusion of extra spot colours and finishes in one print run,” Lebone Paarl Labels general manager Henk Jacobs says. Spot or solid colours are premixed inks used on the press in addition to the CMYK inks. They are found in commercially obtainable colour ranges such as Pantone® and allow for the printing of specific corporate colours or those not replicable by CMYK. These include metallic, neon and opaque white.
“White ink can be a designer’s best friend,” Henk says. “It’s used on its own or as an undercoat before the four-colour process. Printing it under images on transparent films increases the opacity of that design element while on foils it creates contrasting non-metallic areas of print.
“A metallic ink consists of powder-like metallic flakes such as aluminium and copper alloys which are mixed with a varnish or pigment carrier. Metallic spot colours can be printed full tone or combined with CMYK to produce a wide range of metallic and pearlescent colours. Our clients primarily use them as a spot finish on premium wine or spirits labels.”
With HP’s introduction of Silver ElectroInk for its Indigo digital presses printing metallic colours is no longer limited to flexo printing. “Now virtually any metallic colour can be produced by digitally printing process colours over the silver,” Henk says. “This benefits our clients who want digital printing flexibility while saving on additional finishing costs without compromising on metallic effects for a higher-end look.”
HP ElectroInk contains charged pigmented particles in a liquid carrier, combining the advantages of electronic printing with the qualities of liquid ink. It’s loaded into the press in tubular cartridges. “Our HP Indigo digital press offers flexible seven on-press ink stations to cater for CMYK plus metallic finishes and white for sleeves,” Henk says. “The superior liquid ElectroInk technology makes it the only digital colour printing process that matches gravure printing.” Digital inks also cater for yellow and blue inks for security printing with variable data in invisible ink.
Lebone Paarl Labels also offers the printing of PSL using low-migration inks for the food, beverage, cosmetic, pharmaceutical and healthcare industries. Food packaging enterprises are responsible for ensuring that any substances migrating into the packaged food are safe for consumer health. These low-odour and low-taint inks are designed to dramatically reduce migration of chemicals from the ink printed on packaging. They are fast curing, have good adhesion across a wide range of substrates and are foil blockable.
Lebone Paarl Labels has received certification for both a Mellow Colour ISO 12647 Proficient Printer and ImpressionProof, giving clients the confidence that the colours of their PSL designs are printed perfectly to highlight their brands on the shelf.