Showing papers by "Charles H. Giles published in 1969"

Economical and Efficient Fading Lamps

Abstract: 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.

Anomalous Fading of Dispersed-type Fluorescent Brightning Agents-Fading on Film Substrates

Abstract: 染料の日光堅ロウ度は一般に基質上の染着濃度の増加とともに増大する。そしてこの一般的傾向は著者の一人(C.H.G.)の提示した光退色特性曲線(CF曲線)によってよく説明される。著者らは,分散型蛍光増白染料の繊維膜物質上の光退色を定量的に研究しているうち,染着濃度が増すにつれ退色速度が早くなるという明らかな異常現象を見出した。この事実は光退色機構の解明に新端緒をあたえるものと考えられる。本報においては,6-ナイロン,ポリエステル,ジアセテート,トリアセテートの膜中における下記の3種の染料の光退色異常につき報告する。この染料は市販の代表的な耐光性のよい蛍光増白染料のモデルとしてとりあげたものである。光退色機構に関するいっそう詳細な報告に先立ち,若干の一般的考察を併せ試みた。