Osram Bayonet Capped Deluxe Fluorescent

The first generations of white fluorescent lamps were all based on phosphors derived from the natural mineral Willemite (zinc orthophosphate). This normally emits green but in 1936 it was discovered by Osram-GEC that the addition of beryllium could change its colour through yellow to orange and even pink. This was blended with blue-emitting magnesium or calcium tungstate to create a series of white colours, but with rather poor efficacy and lifetime.

In 1942 Osram-GEC made another important development in the history of the fluorescent lamp, with the discovery of the calcium halophosphates activated with antimony and manganese. By adjusting the Sb:Mn ratio the colour could be tuned from a broad blue to broad orange emission, via several shades of white. The original halophosphate materials delivered approximately 30% more light than their silicate predecessors. Another advantage was the possibility to achieve white light from a single phosphor, avoiding the batch-to-batch colour variations from blending the earlier mixtures. Still another advantage was the dramatically lower production cost, and also their non-toxic properties.

However, the colour rendering properties of all of these phosphors was rather poor owing to their lack of radiation at the red end of the spectrum. The next improvements came in the mid 1950s with the so-called Deluxe Whites. These were based on the halophosphates, augmented by pink or red-emitting phosphors such as the magnesium-fluorogermanate that had been introduced for high pressure mercury lamps. This considerably improved the colour rendering, but at the expense of efficacy since some radiation was lost in the invisible infrared region.
Manufacturer: The General Electric Company of England
Lamp Power: 80 Watts
Lamp Current: 0.85 Amps
Lamp Voltage: 103 Volts
Cap Type: B22d/25x26 Brass + Vitrite
Bulb Type: T-38 T-12 in eighths/inch
Bulb Finish: Warm White Deluxe
Electrodes: Coiled-Coil + Anode Plates Triple Carbonate emitter
Discharge Length:
Atmosphere: Hg | Ar
Luminous Flux: 3,200 lm (@ 100h) 2,640 lm (average)
Luminous Efficacy: 40.0 lm/W (@ 100h) 33.0 lm/W (average)
Colour Temperature & CRI: CCT: ~2900K CRI: ~Ra 80
Chromaticity Co-ordinates: CCx: 0.443 CCy: 0.407
Rated Lifetime: 7,500 hours
Warm-up & Re-strike Time: 1 minute Instant
Burning Position: Universal
Nominal Length: 1524 mm 60 inches
Factory: Shaw, Oldham England
Date of Manufacture: March 1956 Date Code: 75
Original Value: £0 13s 0d (1959)
References: 1) Osram-GEC Lamp Catalogue, UK, 1956, p.23
2) Osram-GEC Lamp Catalogue, UK, 1959, p.6