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Economical and Efficient Fading Lamps*

1969; Wiley; Volume: 85; Issue: 9 Linguagem: Inglês

10.1111/j.1478-4408.1969.tb02915.x

2056-5267

C. H. Giles, C. D. Shah, Douglas A. Baillie,

Surface Roughness and Optical Measurements

Tests have been made with over 300 dyed or pigmented materials exposed to mercury‐tungsten or mercury lamps. The colorations were of a wide range of hue and light‐fastness properties (1 to 8 and above) and in several depths on different substrates. The mercury‐tungsten fluorescent lamp (500 W) gave results identical with those obtained with daylight or xenon arclight for 75% of the very varied selection of 174 patterns examined, and 25 % were within one‐half of a grade, except for five which differed by one grade. When the blue standards are faded in this lamp (at 45% r.h.), they have an average interval factor of about 2.1. The required times of exposure are similar to those for the xenon arclight. The equipment required is extremely simple, and its initial and operating costs are considerably lower than those of methods hitherto used for testing in artificial light. The equipment can readily be used on the laboratory bench and is suitable for routine testing of the light fastness of any coloured material. In addition to the control of humidity, temperature control is possible, though this is not usually necessary. The mercury‐vapour lamp (400 W) has also been similarly examined, using 138 patterns. It is not recommended for general use but is valuable for routine sorting tests of materials of very high fastness ( BS grading above 7). The blue standard patterns fade, under exposure to these lamps, in the same sequence and with similar interval spacings, as in daylight or xenon light.