Shedding New Light on Darkroom Illumination
Unfortunately, the needed use of dye filters entails the risk of fading and tampering, so periodic testing and maintenance are very important. The large bulb is also quite fragile, and produces excessive light output for the intended purpose.
Light from these safelights should never shine directly on the film, but only be reflected from the ceiling. Because the large sodium vapor bulbs require a long warm-up time, they must be left on continuously, and so are useful only for general room illumination.
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