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Sylvania Warm Deluxe Mercury H33-1GL/WDX |
Despite the notable improvement in red content and colour rendering, the colour temperature was still rather high. Between 1969 and 1971 Sylvania therefore introduced the Warm Deluxe (WDX) mercury lamp featured here. It is believed to employ a thicker coating of the same vanadate to deliver even more red. This caused a decrease in colour temperature to around 3300-3600K (depending on wattage) which made it more acceptable for indoor lighting. However the chromaticity is shifted slightly below the blackbody locus which gives it a pinkish colour. The extra absorption also decreases the light output about 6-9% vs regular DX lamps, and due to the greater proportion of light generated by the phosphor the lumen maintenance and life was inferior.
In 1975 Westinghouse achieved a further improvement with its Style-Tone /N colour, which delivered a still warmer light but without the pinkish hue. That was originally achieved using a blend of both yttrium vanadate and the earlier magnesium fluorogermanate phosphors. In 1976 Sylvania adopted the same principle with the launch of its Warmtone /N lamp, and the old /WDX was discontinued.
This particular lamp is old enough to still feature the famous Sylvania girder-frame unitised mount assembly, which delivered a notable improvement in mechanical strength.
| Manufacturer: | GTE Sylvania | |
| Lamp Power: | 400 Watts | |
| Lamp Current: | 3.25 Amps | H33 or H1 Ballast |
| Lamp Voltage: | 140 Volts | |
| Cap Type: | E39s/41 | Ni plated brass + vitrite |
| Bulb Type: | BT-117 | BT-37 in eighths/inch |
| Bulb Finish: | WDX Phosphor | Leaded Borosilicate |
| Electrodes: | Backwound tungsten | Double carbonate emitter |
| Arc Length: | ||
| Atmosphere: | Inner: Hg | Ar (5 atm) | Outer: Nitrogen |
| Luminous Flux: | 21,000 lm | @ 100 hrs |
| Luminous Efficacy: | 52.5 lm/W | @ 100 hrs |
| Colour Temperature & CRI: | CCT:3600K | CRI: Ra47 |
| Chromaticity Co-ordinates: | CCx: 0.400 | CCy: 0.380 |
| Lifetime: | 24,000h to 50% survival | 10,000h to 70% lumens |
| Warm-up & Re-strike Time: | 4 minutes | 15 minutes |
| Burning Position: | Universal | Horiz. lumens 5% less |
| Overall Length: | 292 mm | 11½ inches |
| Light Centre Length: | 178 mm | 7 inches |
| Factory: | Drummondville | Canada |
| Date of Manufacture: | June 1973 | Date Code: 30 |
| Original Value: | US $16.50 (1973) | |
