RLOD#32 (2020.06.14) 1989 Tungsram HgMIF 250/D

Lamps produced by Tungsram of Hungary were of the highest quality in the Eastern Bloc. The HgMIF 250/D shown here is an example of their attention to details, which often matched that of Western manufacturers. This is a daylight metal halide source of the second generation with a single-piece arc tube filled with a blend of thallium and rare earth iodides, balanced for the production of 6000 K light with an extremely high color quality. In order to extend the mean service life by 50 % to 9 kh the Hungarians widened the outer bulb to 52 mm so as to reduce the hydrogen effusion rate from the borosilicate glass material, and they increased the electrode gap length from 20 to 32 mm to lower the wall thermal load of the burner. While effective, these changes also caused the initial flux output to drop by 3 klm to 17 klm (-15 %) and the operating position tolerance remained limited to horizontal ±45° to ensure an optimum regime (the light color properties remained unchanged over the previous lamp generation). Such life-output trade-off is typical for HID lamps and with the HgMIF 250/D Tungsram clearly prioritized the lamp's durability over its initial performances.