Osram HCI-TC 70W/WDL Shoplight

Here's a very interesting development in ceramic metal halide technology. In 2006 Osram released a "Shoplight" variant of its Powerball HCI featuring a light color quality raised by 10 Ra8 points and an increased red output, bringing the red rendering index to a positive value (50 R9 !!). The steps taken to achieve such impressive changes were relatively simple: the arc length was shortened in order to raise the arc power load, the mercury vapor pressure was increased to broaden sodium's molecular emission in the red end of the spectrum, and calcium iodide was added to an otherwise standard Na-Tl-Dy-Ho-Tm iodide fill chemistry so as to increase the red output further. The result is a very pleasant warm-white light color (the HCI Shoplight was not available in any other color) that was particularly suited for retail lighting applications, the targeted market for that lamp. Its light emission spectrum can be seen here and can be compared to that of a standard warm-white ceramic metal halide lamp.