1979 Narva NC1000-62

In 1969 Osram of (then) West Germany introduced the breakthrough HMI, a compact rare earth halide short-arc lamp that revolutionized the stage-and-studio lighting industry and proved invaluable to color TV broadcasting, which emerged in the Federal Republic of Germany two years prior. While the lamp proved highly effective in its application, delivering artificial daylight at high efficiency, its adoption was limited by a high cost price resulting from the need for advanced production techniques and the use of components of very high quality and purity. Narva of East Germany entered this market three years later by following a different and more economical approach, one that required significantly less investment and resulted in much cheaper lamps.

Narva released its first stage-and-studio metal halide light source in 1972, about two years after the company began producing metal halide lamps in late 1969. The new lamp initially bore the HQI1000C reference, which was changed to NC1000-62 the following year. This light source was simply a color-improved variant of the company's standard daylight NTI-filled (i.e., Na, Tl, In iodides) 1 kW HQI, to which a dose of red-emitting lithium iodide was added so as to increase the light color quality by 11 R8 points to a CRI of 73 Ra8. While mediocre compared to that of Osram's rare-earth halide HMIs (90+ Ra8), the emission spectrum of the NTI+Li fill chemistry still proved satisfactory for color TV broadcasting, which became the primary application of Narva's lamp, focused specifically on studio and outdoors lighting. Because of its intended usage in multiple units in cylindrical parabolic reflector luminaires, the NC1000-62 is fitted with a tubular outer jacket and is specified for an operation in the horizontal position with a tolerance of ±2° only in order to minimize lamp-to-lamp color variation. Interestingly, and typical of Narva’s 1 kW metal halide lamps, the NC1000-62 is designed with an arc voltage of 220 V, suitable for an operation on 380 V three-phase mains circuits.

While the addition of lithium is the key to a better light color, it also has a critical impact on other properties of the lamp. Compared to Narva's standard NTI-filled 1 kW HQI (later the NC1000-00), the lumen output decreased by 10 klm to 80 klm, the light color temperature dropped by 1000 K to 5000 K, and the mean service life was shortened to 2000 h only due to the high chemical reactivity of lithium iodide. The latter was not a critical issue in the targeted application, especially given that Osram’s HMI lamps have an even shorter lifespan due to their much higher power load. Nevertheless, the NC1000-62 has significantly inferior light technical properties overall but the near monopolistic position of Narva in the East German lighting market led to the lamp being produced with a virtually unchanged design until the early 1990s. The company even released another color-improved NTI-filled metal halide lamp, the NC1000-63 with a 3200 K color temperature and a CRI of 70 Ra8, intended for a usage with tungsten-balanced film stock.