DYSPROSIUM IODIDE LAMP AND ITS USE IN PHOTOENGRAVING
镝灯研制及其在照相制版中的应用

The working principle, structure and characteristics of a dysprosium iodide lamp are described. It is a vapour discharge lamp containing a mixture of dysprosium iodide and halmium iodide. With a lifetime of 200 hours, its luminous efficiency is above 70 lumen/watt and its colour temperature 6000 K. Trial applications in photoengraving show that the dysprasium-iodide lamp, as compared with the carbon-arc lamp, has the virtues of higher brightness, smaller dimensions, and greater stability and cleanness. As a new type of light source it is expected to improve the art of photoengraving.