Why the blue/green lens in early taillights?

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dykker5502
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Why the blue/green lens in early taillights?

Post by dykker5502 » Sun Mar 22, 2020 8:10 pm

I have a question that the early Ford guys or brass guys may know the answer for. I have searched the old forums and I can see that the question have been raised before but never really answered:

Why do brass era taillight have this blue/green lens towards left? In UK with RHD the glasses are mirrored and the green lens is towards right.
And do not come with the crab (sorry) about naval lightning as green is to the RIGHT and we do not have any red towards Left - towards left the light looks GREEN,
Was it legislation? What is the purpose?
The best explanatinon I've seen was that in a crossing those comming from your left must yield for you. In the dark, when they see your green sidelight, they know your car has passed and they can proceed.

Can you come up with a better?
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DanTreace
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Re: Why the blue/green lens in early taillights?

Post by DanTreace » Sun Mar 22, 2020 8:58 pm

The rationale perhaps was deciding on green for a tail lamp, early autos used green for tail lamp color, then later red became common.

In practice, the kerosene flame burns yellow, so when projected thru a blue lens, the exit light is green.

http://www.mtfca.com/discus/messages/59 ... 1465851863

An older post above shows photos on the subject that a blue lens with a flame shows green.

Even in 1925 some USA states allowed green tail light.
1925 auto lighting requirements.jpg
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Re: Why the blue/green lens in early taillights?

Post by DanTreace » Sun Mar 22, 2020 10:07 pm

Generally all the early tail lamps were made with a green light to the outside, as indicator of moving vehicle, a white light to illuminate the presence of a license plate, and red danger light projecting to the rear, to warn approaching drivers.

Definitions from automobile terms , Horseless Age, 1912

Screenshot 2020-03-22 21.59.47.png
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Re: Why the blue/green lens in early taillights?

Post by Susanne » Sun Mar 22, 2020 10:28 pm

You nailed a question that has bnothered this 20th (maybe 21st) mind for a long time... I have a pierce arrow rear tail light assembly that has green and white to the rear, but no red, and I know the red tail lights were standardized in the 1950's, but even knowing this it throws me for a loop... because, were other colors common back in the day, and if so, what were they????

This has bothered me since I was a kitten (and I am way older than kitten status), but that tail light in my storage still sits there and taunts me, a conundrum yet to be solves....

Any ideas, answers, or WAG's ????

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Re: Why the blue/green lens in early taillights?

Post by JTT3 » Sun Mar 22, 2020 11:06 pm

I have a pair of triple tier E&J patent pending side lights with the red jewel on the drivers side and a blue jewel on the passenger side I thought that unusual and started to investigate. All I could find that made sense is the relationship to maritime law in 1848 for navigation, red being port side (left) green being starboard (right). Your mileage may vary. I’d like to hear what others may opine.

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Re: Why the blue/green lens in early taillights?

Post by Mark Gregush » Mon Mar 23, 2020 2:09 am

What John said is what I understood, also railroads.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: Why the blue/green lens in early taillights?

Post by Jem » Mon Mar 23, 2020 3:37 am

Looking at some lights on a Frenchman's stall at Beaulieu Autojumble some years ago, I asked why the LH of each pair had a white window with blue or green chevrons(like the Citroen badge).

The French have, or had, 'priority to the right' - the fellow coming out of the road on your right will shoot out in front of you. A horse- drawn vehicle has plain white so you can see he's there. A motor vehicle has chevrons so you know it's approaching the junction faster.


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Re: Why the blue/green lens in early taillights?

Post by Allan » Mon Mar 23, 2020 4:26 am

Susanne, your Pierce Arrow rear tail light certainly is a connundrum. Can you tell us what a front tail light looks like? :D

Allan from down under.

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Re: Why the blue/green lens in early taillights?

Post by Susanne » Mon Mar 23, 2020 8:25 pm

It looks like a rear one, but mounted backwards. Has to do with the reverse flow of electrons to project a light in front of a vehicle, instead of letting the light hust toss them out there to be absorbed eventually by the ether... :mrgreen:

That was why early headlights ran on acetylene - it needed the force of the pressurized gas to push all that light against the direction of travel, otherwise it would all end up bunched at the reflector.

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Re: Why the blue/green lens in early taillights?

Post by J1MGOLDEN » Mon Mar 23, 2020 8:29 pm

I was recently told that the original Ohio Law requiring a vehicle to have a light that came on when braking specified that light should have a green lens.

I have not seen that in print.

When I was real young, my dad wired his cowl lights to be always on at night along with the head lights.

He was a merchant seaman and he painted them red and green for port and starboard.

We got stopped by a police officer that gave him a ticket that resulted in a $10 fine, a lot of money in 1940!

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Re: Why the blue/green lens in early taillights?

Post by TRDxB2 » Mon Mar 23, 2020 9:01 pm

An INTERNET search reveled several sites. To start red yellow and green are the most distinguishable colors in daylight. "Most of the key colored-light standards we use today came from railroad developments. Take the now wildly standard red-stop/green-go dichotomy. That came from railroad signals. Red seems to have been chosen from its centuries-old association with danger, which shows up in nature as well — many poisonous berries and insects are bright red, and you can’t forget that one of our most basic visual associations of danger — large splashes of blood — are quite red as well. Red is noticeable, and we seem to have some natural pre-disposition to read it as an alarm color. Now, originally, the ‘go’ color was just a white lantern, but an incident in 1914 where a red lens fell out of a lantern and caused a train to go instead of stop, causing a wreck, soon proved the problems there. Originally, green was used to signal ‘caution’ but the need to differentiate ‘go’ from a simple white light caused the job change of green to mean go. Yellow seems to have been picked for ‘caution’ because of its easy visibility and distinguishable from the other two colors."
Also there was a marker light system for trains, and the rules stipulated that there must be a red marker light to delineate the end of a train. Perhaps too, blue lens for yellow flamed gas lamps to produce a green light was intentional as well.
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Re: Why the blue/green lens in early taillights?

Post by PeterN » Wed Mar 25, 2020 6:49 pm

Peter N

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