Microsoft word - lightfastness

Light Fastness of Coloured Anodised Aluminium by Polychromal

Test institute
The enclosed tests were performed by the Atlas Weathering Services Group Europe of Atlas Material Testing
Technology (MTT) GmbH. The European test laboratories of Atlas MTT in Duisburg (Germany) and Paris (France)
were accredited to DIN EN ISO/IEC 17025:2000 by the Deutscher Akkreditierungsrat (DAR), an internationally
renowned accreditation council affiliated with the Federal Institute for Materials Research and Testing of Germany.
The Atlas Weathering Services Group (AWSG) is one of the largest networks of ISO/IEC 17025 accredited
accelerated weathering testing laboratories in the world. With laboratories in France, Germany and the United States,
AWSG’s indoor exposure laboratories offer artificial accelerated weathering tests and a variety of other environmental
test programs, all designed to accurately simulate true end-use conditions and meet global weathering standards.
Both labs in Duisburg and France have proven over many years to provide reliable test results to international
customers. The accreditation stresses the laboratories’ obligation to identify clients’ needs and ensures the test
methods chosen meet those needs.
The facilities in Germany and France conduct accelerated weathering and light fastness testing. Featuring a variety of
xenon, carbon-arc, fluorescent and metal halide weathering instruments, they can meet most accelerated test
methods from corporate, national and international standards organizations.
Test method
The test method used is defined in ISO 2135 “Anodizing of aluminium and its alloys – Accelerated test of light
fastness of coloured anodic coatings using artificial light’’ second edition 1984-02-01.
This International Standard specifies an accelerated test method for assessing the fastness, using artificial light, of
coloured anodic oxide coatings on aluminium and its alloys. The resistance of the colour in the anodised layer to the
action of a standard artificial light source is determined. A Xenon lamp is used, having an emission wavelength profile
close to daylight. D65 is the internationally recognized emission standard for outdoor daylight as defined in ISO 10977
(1993). Light sources conforming to the D65 emission standard should contain UV and visible spectrum, such as
Xenon lamps.
Filtered (D65) Xenon discharge lamps are full-spectrum light sources and simultaneously expose in the UV, Visible
and IR spectral regions. The Atlas SUNTEST meets the D65 spectral criterion with an optical filter system consisting
of a coated quartz glass dish (P/N 56052388) and an UV special glass filter (P/N 56052371).
Evaluation
Anodised samples are exposed to artificial light and regular observations are made of any colour change by
comparison with the grey scale DIN EN ISO 20105-A02 (1994): Grey Scale for Assessing Change in Colour. This
standard consists of a nine half-steps scale from 5 to 1 representing a visual difference and contrast. The grey scale
has nine possible values: 5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2 and 1.
Polychromal b.v. Mailaddress: P.O. box 8043 ● 1802KA Alkmaar ● The Netherlands ● Phone: +31(0)72 5670790 ● Telefax: +31 (0)72 5670795 ●
Homeaddress: Marterkoog 8 ● 1822BK Alkmaar ● Internet: www.polychromal.nl ● E-mail: [email protected] ● Registered: K.v.K. Alkmaar 37044908 ●
VAT No. NL 00 15 14 726 B01 ● Bankers: ABN Amro Bank B.A. No. 54.70.10.117 ● IBAN NL82ABNA0547010117 ● BIC-code: ABN ANL 2A
To all our quotations, to all orders given to us, and to all contracts concluded with us outside the Netherlands the Metaalunie Conditions for the supply of mechanical, electrical and associated electronic products are applicable. These general Conditions will be send to you at your request. Op al onze offertes, op alle opdrachten aan ons en op alle met ons gesloten overeenkomsten zijn toepasselijk de METAALUNIEVOORWAARDEN. Grade 5 means no visual colour change (best rating) and grade 1 means a large visual change (worst rating). For the
visual inspections, the exposed part of a sample is compared with an unexposed reference sample.
The apparatus and light source were calibrated by exposing a coloured cloth sample (Blue wool) having a light
fastness number of 6 on the European blue scale (ISO 105-B01). The time of exposure was determined for the Blue
wool to show a colour change corresponding to grade 3 of the grey scale. This length of time was 200 hours and is
defined as the exposure cycle for the apparatus.
Coloured anodised specimen of unknown light fastness were exposed under the same conditions as the Blue wool
sample for 4 cycles. This resulted in a test time of 800 hours, which is generally equal to 9 months of outdoor
exposure in middle Europe according to ATLAS Material Testing Technology GmbH. Visual inspections were
performed after 400, 600 and 800 hours.
The light fastness number is a function of the number of exposed cycles required to produce the appropriate colour
change corresponding to grade 3 of the grey scale (about 25 % loss of colour). Two of these cycles corresponds to a
light fastness number of 7 and four of these cycles to a light fastness number of 8.
Apparatus
The samples (35*35 mm plates) were tested in a Suntest® XLS+ test instrument, with a Xenon Arc light source. An
UV filter (suprax) / coated Quartz filter system was used. The irradiance was 550 ± 50 W/m2 between 300 to 800 nm,
with a continuous light cycle. The black standard temperature was 42 ± 3 oC (needs to be below 50 oC) and the dry
bulb temperature was 35 ± 2 oC. The position of the exposed specimen in the apparatus were switched after each
cycle, ensuring an identical distribution of light on each sample.
Results
Duracolours on Duraseal
Duracolours Yellow, Cyan, Magenta and Black were digitally printed in Duraseal mat at 1440x1440 dpi with the DS-printer using 4 colours: Cyan (C), Magenta (M), Yellow (Y) and Black (K). Table 1: light fastness numbers of DuraColours in Duraseal mat. Polychromal b.v. Mailaddress: P.O. box 8043 ● 1802KA Alkmaar ● The Netherlands ● Phone: +31(0)72 5670790 ● Telefax: +31 (0)72 5670795 ●
Homeaddress: Marterkoog 8 ● 1822BK Alkmaar ● Internet: www.polychromal.nl ● E-mail: [email protected] ● Registered: K.v.K. Alkmaar 37044908 ●
VAT No. NL 00 15 14 726 B01 ● Bankers: ABN Amro Bank B.A. No. 54.70.10.117 ● IBAN NL82ABNA0547010117 ● BIC-code: ABN ANL 2A
To all our quotations, to all orders given to us, and to all contracts concluded with us outside the Netherlands the Metaalunie Conditions for the supply of mechanical, electrical and associated electronic products are applicable. These general Conditions will be send to you at your request. Op al onze offertes, op alle opdrachten aan ons en op alle met ons gesloten overeenkomsten zijn toepasselijk de METAALUNIEVOORWAARDEN.

Source: http://www.polychromal.nl/fileadmin/user_upload/polychromal.nl/Products/Downloads/Testrapporten/EN/lightfastness_Duraseal.pdf