Hi r/AskHistorians! I've wondered this question for a long time, but I'm having trouble finding an actual answer that isn't purely speculation with no background research.
When Ftizgerald writes about "the green light" in The Great Gatsby, does anyone know what the light would have actually looked like? The book was published in 1925, and I've tried researching things like "dock lights from 1925" but that hasn't given me much information either.
It's one of my favorite books, and I would really love to know a factual answer. If this isn't the most accurate subreddit to ask, I'm sorry!
It would simply have been a "green light". I'm not trying to be facile here, but private docks, yacht berths and the like have, since the development of electric lighting, been indicated by electric lights. The colours are almost invariably white, red or green. The colours are achieved by the use of coloured glass encasing the conventional "white" light bulb. The actual lights, as viewed from the sea, are listed in this Admiralty publication http://www.ukho.gov.uk/ProductsandServices/PaperPublications/Pages/NauticalPubs.aspx in several volumes. The "Green Light" on Daisy's husband's dock would simply have been a green electric light, and would look the same as any green electric light, based on a conventional light bulb, that one might see now. I hope that helps.
maybe try r/boating?