From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Improvements to instrument board lighting, focusing on bulb colour and voltage.
| Identifier | ExFiles\Box 62\2\ scan0063 | |
| Date | 18th April 1932 | |
| S/W. (c. to Hs.{Lord Ernest Hives - Chair}) WST X6141 Cx{Major Len W. Cox - Advertising Manager}5/KW18.4.32. Instrument Board Lighting. Thanks for your E.3/HP15.4.32, from which I note that you are working to improve the illumination of the present instruments. What we feel we should like best is a uniform illumination of the dials sufficiently brilliant with the use of green coloured bulbs to make the instruments easily legible at night. There would, we think, be too much dazzle effect at night through the instruments being illuminated with a white light. In 64-JS{Mr Johnson's Secretary}, which just delivered to a customer, we had a similar repetition of the ineffective lighting of the instrument board. The lamps were green and we find they were 16-volt. Would you please say when corresponding further on this question whether there was any special reason for using 16-volt lamps on a 12-volt circuit. In this case to make the instruments legible we had to remove some of the green from the lamps. Cx.{Major Len W. Cox - Advertising Manager} | ||