Lightfastness
Almost every carpet or textile will brighten or fade in colour over time. The damage level is determined by various elements, including colour, dye technique, location, exposure, and light intensity.
When looking for the appropriate fabric, you may have encountered the phrase "lightfastness." Perhaps you've seen a lightfastness grade or a certain number of light hours written on a fabric's specifications, but you weren't sure what they meant or fully grasped their relevance. Let's talk about it!
Lightfastness is defined as "the extent to which a dye resists fading owing to continuous light exposure." Although this is especially significant when selecting fabrics for a sunroom or outdoor use, it is crucial to realise that all dyes are susceptible to light damage. Fading issues typically arise when the fabric is not designed to fit the ultimate usage. Light fastness is best described as the number of average daylight hours an upholstery fabric can receive before showing signs of fading.
Why is the colour of a fabric important?
The colour of a fabric is one of the main attributes in its selection process. Colours can reflect trends, compliment spaces or be a personal favourite. Whatever the reason behind selecting a colour, it is vital to maintain its appearance. Our fabrics are used for a vast array of products, which means they are subjected to several different conditions. For example, a sofa placed within a large bay window would be exposed to long hours of the sun's UV and visible light rays, which can alter the colour's appearance over time.
In house testing
One of the first stages in our new product development process is to ensure the reliability of the fabric's colours. We do this by testing the light fastness of the shades in our in-house laboratory, FITT. Light fastness is the degree to which the fabric changes colour due to light exposure over a period of time. So, to maintain a colour's appearance, our fabrics must have a high colour fastness.
Light fastness testing method
The colour changes can include changes in hue, chromatic characteristics, fading or a combination of these characteristics of colour. A fabric specimen is put onto cards and then into the light fastness machine, along with reference materials. Any changes are compared to these references and are then rated on a scale of 3 to 5, with 5 being the target level of change for fabrics suitable for general domestic use and 3 being significant changes in appearance. Some colours are more susceptible to light exposure. To ensure that our ranges have a full array of colours, we increase our focus on improving any failing colours in the preliminary selection stages through a lengthy colour development process.
Manufacturing processes affecting a fabrics colour
It is important to note that upholstery fabrics undergo many treatments to comply with health and safety standards, such as fire retardancy. These processes usually expose the fabric to high temperatures, which might affect the dye. It is crucial to test the light fastness of the fabric after any treatment processes to ensure that it has not affected its lightfastness rating.
Maintaining standards
We firmly believe that to maintain our high-quality standards; we must implement regular testing throughout the fabric's life cycle. Samples are taken from our stock to check for colour fastness, highlighting any improvements that need to be made.
Intended use affects the fabric's colour.
It is crucial to keep in mind the intended conditions of the fabric. A shop window display would expose the fabric to higher levels of UV and visible light rays, which means that the fabric will have a lower lightfastness rating compared to the standardised conditions in our in-house lightfastness machine. Other factors, such as heat and humidity, can also influence the dye degradation rate of fabrics. To take care of the fabrics, it is key to situate them in appropriate conditions or to source fabrics with a higher light fastness rating.
Find out more about our in-house testing facility FITT here.
