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In the 1980s, I made hundreds of images of upper quadrant three-position semaphores along the old Erie Railroad in New York State, a line then part of the Conrail system.
I focused on this semaphore near Tioga Center, New York in August 1988. This is part of a sequence that portrayed the signal in its three position and this image is of the ‘approach aspect’.
Learn more about American semaphore practice in my book, Classic Railroad Signals published by Voyageur Press.
Glad to help.
If I feel ambitious, one of these days I’ll write an introduction to deciphering color technique and terminology.
Brian, thank you for taking the time to give this detailed reply. Color is so tricky in so many ways!
The semaphore lenses (roundels) were carefully tinted to render specific color hues as prescribed by agreed-upon signal standards. (I detail this in my books on the subject). However, since the colors are altered by the light source they must compensate for this. The signal light viewed by the train crew is produced by a low-voltage incandescent lamp which has a yellowish color—owing to warm color-temperature of the lamp in the vicinity of 3,200 degrees Kelvin. Daylight, by contrast, is closer to 5,500 degrees Kelvin. To compensate for the yellowish incandescent light, the colored roundel for clear has a bluish tint so that the end result appears the correct green hue as appropriate for a ‘clear’ aspect. Semaphore roundels used with paraffin lamps have an even more bluish hue, since the color temperature of the light is even warmer than that of the tungsten electric light.
The Kodachrome emulsions were especially difficult to obtain consistent color balance. I was unusually fussy back in the 1980s, and would often use PKM (Professional Kodachrome 25) that I’d keep frozen until a day or so before exposure, and then send out for processing immediately. Off the shelf K25 (which I also often used) was best about 1-2 months before its expiration date. Those of us fussy about color, would buy bricks of film and let it age until that time and then freeze it until we needed it. K25 used too soon would have a cyan hue, Kodachrome that had gone by its date would shift towards the red/magenta.
Offhand, I don’t recall which emulsion I was using for this slide, but the overall cast is ever so slightly (3-5 cc) cyan. However, as stated above, that is not the reason for the roundel appearing cyan blue.
I’ve found the most effective time of day to photograph color light signals is near dusk when you can better balance the ambient light with that of the signal. Also, you must turn the ‘auto white balance’ off, or the camera will try to compensate for the color of the signal light. ‘Daylight white balance’ is a better choice, but not perfect.
I hope this helps,
Brian Solomon.
When I went trackside with a digital camera and not too much experience, I found it very difficult to get lit signal lights the correct color and intensity whenever they were an important part of a scene day, dusk, or night.
In 1988 you were a skilled photographer. Please explain the green lens appearing blue in this photograph. Is this an artifact of Kodachrome 25?
I’ve noticed in software that attempts to emulate film that Kodachrome emulations always seem to have a magenta cast.
Well, well we seem to get a lot of semaphores! Nice, keep it coming!