An Instrument makes Industrial History - 50 Years ago the Weathering Testing Instrument Xenotest® 150 was introduced

Linsengericht / September 2005 - Most of us are annoyed when their sports dress loses colour and form, the seat fabric inside of a car or the carpet bleaches too fast. Sunlight and other weathering factors, such as humidity, harm colours and the structure of fabrics and other materials. To do light- and weather fastness testing, the materials are tested in instruments which are able to simulate the effect of light and weather on a material. This year one of these remarkable instruments celebrates its 50th anniversary: The Xenotest

A Brief Look Back into History:
During the 19th and 20th century synthetic dyestuffs started to replace natural pigments and soon test methods were required to compare the new products respectively the dyestuffs. As a consequence, in 1911 chemists founded the German Textile Fastness Committee (DEK) and developed a standardized test method for light fastness. Light fastness depends on light and weather as well as physical factors like washing, cleaning, bleaching, ironing. The effect weather has on textiles can be tested by Weather-Ometer and Xenotest® instruments manufactured by Atlas MTT.
During the first light fastness tests dyestuffs and printed textiles were exposed behind window glass to natural sunlight. Soon it was noticed, that different test sites led to different results and that the tests turned out to be extremely time consuming. Thus artificial light sources were required to be able to simulate natural sunlight and accelerated the testing procedures. But quartz and carbon arc lamps as well as other light sources did not meet the requirements.

The Artificial Sun:
A solution was not found until the 50ties, where more and more synthetic colours and fibres were developed. As people were longing to show more colour, after World War II, a chemist of Frankfurts dyestuffs company "Cassella", Mr. Klaus Toepfer, who was also a member of the Textile Fastness Committee, was seeking for a manufacturer of lamps and found the ideal partner, the company "Original Hanau Quarzlampen". In close collaboration they developed the first Xenotest® instrument with on xenon arc lamps. The benefit was, that its light simulated the sunlight at the closest. Soon the Xenotest® 150 was built around it and testing time was reduced down to a tenth compared to tests with natural sunlight. Therefore the German standard of light fastness was tailored around this instrument. As a result, light fastness of dyed and printed textiles had to be proven according to the German light fastness standard using a Xenotest® instrument. Years later the benefits of xenon arc lamps were also recognized on an international level and the lamp was used for various other needs.

Rain Follows Sun:
After its introduction to the market in 1955, the Xenotest® 150 soon evolved. A special humidity and rain system ensured that besides light fastness also weather fastness of specimens could be proven. Nowadays an advanced system including microprocessor, sensors, control units and filters ensure that the light- and weather fastness of nearly all textiles can be tested.
At first merely the textile industry, with clothing and technical fabrics, needed the Xenotest® 150, but currently most of the Atlas instruments are located in the automotive industry for testing plastics, coatings and car interior materials.
Today many Atlas customers still have the Xenotest® 150 in regular use.
One of these remarkable instruments will be shown at the International Symposium, celebrating its 50th anniversary along with the 75th DEK Annual Meeting in October in Erding (near Munich, Germany).

Atlas MTT is a manufacturer of material testing devices and offers natural as well as laboratory weathering services. In 1995 the American company Atlas MTT LLC, located in Chicago, incorporated the Xenotest® GmbH, a former division of the Heraeus Group.