by Danny Mertens
What is lightfastness and why is it important?
Lightfastness is critical for high quality labels. It is a measure of how well a printed image resists discoloration or fading as a result of exposure to light over time. Products sitting on a store shelf or in a warehouse are often exposed to direct sunlight for hours on end. The UV affects the color pigments, causing the image to lose its brightness over time. It is a natural process which can be slowed down by adding protective UV layers on top of the label (varnish or laminate).
However, the most sensible – and most efficient – way to go forward, is by using quality inks or toners. Varnishes and laminates can only do so much – it really is the quality of the toner or ink that determines whether or not a label stands the test of time and keeps on shining on the shelf even after months.
Drum labels, chemical labels, house hold labels, pharmaceutical labels and BS 5609 certified labels all have specific requirements in terms of lightfastness. The latter are labels which are transported oversea. These need to remain legible even after weeks or months of damp conditions at sea.
Lightfastness and the Blue Wool Scale
Lightfastness is typically determined using the Blue Wool Scale, which measures the colorfastness to natural daylight of a color by comparing it to a blue wool standard, hence the name. Originally developed to compare the fastness properties of textile dyes, it is expressed on a scale of 1-8, where 1 is the lowest value. A rating of 6 means “very good lightfastness”, while 7 and 8 indicate “excellent lightfastness”.
From the start, Xeikon invested in high quality toners with great lightfastness scores without any additional protective finishing. The goal was to achieve this for both CMYK and spot colors (with the exception of spot color blue which is generally known to be very receptive to UV). Several independent tests have shown that all current Xeikon process colors meet or exceed rating 6 on the Blue Wool Scale. In other words, with Xeikon toner your prints will remain their vibrant selves for a very long time.
Several independent tests have shown that all current Xeikon process #colors meet or exceed rating 6 on the #BlueWoolScale.
QA I toner – specifically developed for the label industry
The QA I toner was designed to meet the high quality standards of the packaging and label industry. A test carried out in 2011, comparing QA I toner with liquid toner and UV inkjet, proved Xeikon’s superiority. All labels had to endure 800 hours of exposure to sunshine outdoors. The results speak for themselves:
ICE toner and Cheetah toner, quality printing on heat sensitive substrates
ICE, Cheetah and other toners specifically designed for the label industry, combines all the benefits of the QA I – lightfastness, image quality, food safety, … – while adding another great feature: it is highly suitable for printing on heat sensitive substrates, such as PE and direct thermal paper labels.
Want to know more about Xeikon toner? Get in touch.