Imagine you’ve spent days, weeks or month working on a piece to sell or display in your own studio. You then hang it on the wall where it fades significantly in just a few months… which is not what you want. Luckily, you can enjoy your work for years to come by using professional artist materials carefully developed to resist fading. Liquitex acrylic color is designed to be lightfast, meaning it offers artists the longevity and permanence they need. Learn more about lightfastness, and why it plays such an integral part in how we test color.

WHAT IS LIGHTFASTNESS?

Lightfastness the measurement of how chemically stable a material is when exposed to light. In scientific terms, a chemical reaction called photo-degradation happens when light hits a surface. This is when the chemical bonds between the molecules alter or break causing fading or a change in color. The longer it resists, the more lightfast it is.

WHY IS LIGHTFASTNESS IMPORTANT?

You don’t want your work fading away. If you’re after an archival result that will withstand the test of time, you need to use materials that are lightfast.

For art materials, it’s all about the pigments or dyes used. Some pigments are naturally more lightfast than others. The format also makes a difference. A pigment in a water-based formula may have a different rating when it’s in an acrylic.

However, while these colors may break down in UV light faster than other pigments, they do offer artists a unique color experience, and the benefit of an expanded palette may outweigh the benefit of extreme lightfastness.

HOW IS LIGHTFASTNESS MEASURED?

Testing is typically done by exposing a color to sunlight, or with an artificial light in a Xenon arc lamp machine… which speeds the process dramatically.

HOW DO WE TEST LIGHTFASTNESS?

At Liquitex we work with the highest-grade fine art pigments with good lightfast ratings. When a new color is formulated, it’s painted onto swatches. These head into our laboratory xenon machine and blue wool standard. The process takes around three weeks. We do our own in-house Blue wool test for Permanence rating where we test all our colours.

HOW DOES THE TESTING MACHINE WORK?

The Xenon Arc Machine uses an arc of ultra-bright xenon lights to replicate ‘real’ light conditions. In other words, the machine replicates the process of colors being exposed to natural daylight filtered through a glass window. The bulbs produce white-blue light in full spectrum UV, visible light and infrared rays.

Two to three times brighter than a halogen, the Xenon chamber is a turbo-charged version of real life. It lets us accelerate the process. When paint swatches are put in the machine for 300 hours and blasted with light, which is equivalent to 100 years of studio conditions. We also use Blue Wool scales standard that we put in with the samples each time we conduct a test. Then, we remove the swatches and observe the change.