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Author Topic: Why red, yellow, and green?
Mojo Jojo
The Red and the Green Stamps


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Today in Geometry. (Yes, Geometry...tomarrow we have a mid-term....) Anyway, my teacher brought up the subject of stop lights. He asked us why they choose Red for Stop and Green for Go. he said something about blood or something and he just rumbled about how if you go you'll wreck and get blood everywhere or something...he had no idea what he was talking about. I thought the reason why Red was for stop was becuase red (out of the primary and secondary colors) was the color that stood out most.
Could someone please tell me why or where I could find why these three colors were chosen for stop lights?

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Kathy B
Angels Wii Have Heard on High


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Uncle Cecil covers it
Who decided red means "stop" and green means "go"?

Posts: 4255 | From: Sacramento, CA | Registered: Feb 2000  |  IP: Logged | Report this post to a moderator
The Evil Spam Gamgee
The Red and the Green Stamps


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I'd have thought that the colour which stands out most is the one to which the human eye is most sensitive, namely green...
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captain1
The Red and the Green Stamps


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Just looking from a physics point of view (doesn't answer the question but is interesting none the less)

Red and Green are totally seperate colours (ie they are one of the two primary colours) so even with any form of filter the one cannot be 'seen' as the other. (ie put a yellow filter over a red light you get red.. over a green light you will get green)

Now more interesting is that if you combine red and green you get yellow..


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Chava
The Red and the Green Stamps


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quote:
Red and Green are totally seperate colours (ie they are one of the two primary colours) so even with any form of filter the one cannot be 'seen' as the other.

Unless you happen to be red-green colorblind (the most common form of colorblindness).

Chava


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dilbert
The Red and the Green Stamps


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quote:
Originally posted by Chava:

Unless you happen to be red-green colorblind (the most common form of colorblindness).

Chava


That's why they have standard location


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abbubmah
Ding Dong! Merrily on High Definition TV


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quote:
Originally posted by dilbert:
That's why they have standard location

In Texas they're horizontal with red on the left.

Confusing? Sure, but it's Texas. It's the standard Texas location.

Uncle "not mounted drag strip style." Bubba

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Fundamentally Unfundie since 1975


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Mojo Jojo
The Red and the Green Stamps


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quote:
Red and Green are totally seperate colours (ie they are one of the two primary colours) so even with any form of filter the one cannot be 'seen' as the other. (ie put a yellow filter over a red light you get red.. over a green light you will get green)

Isn't Red, YELLOW, and Blue the three primary colors? or am I confused as usual?

Thanks for the information!


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bufungla
Let There Be PCs on Earth


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quote:
Originally posted by Mojo Jojo:
Isn't Red, YELLOW, and Blue the three primary colors? or am I confused as usual?

In pigments, yes - in light, no. See this thread.

buf 'confusion - will be my epitaph' ungla

--------------------
"Pardon him. Theodotus: he is a barbarian, and thinks that the customs of his tribe and island are the laws of nature."

George Bernard Shaw, Caesar and Cleopatra


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BlueRose
The Red and the Green Stamps


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Yellow (or to be more precise in this case, amber) is actually the most visible of the three lights. Yellow against black actually has more visual impact than white against black, so i was told, and that's why yellow/amber is the caution light.

Blue "red means stop, green means go, yellow means go very fast--anyone know which movie that line's from?" Rose


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Jaime Vargas Sanchez
Let There Be PCs on Earth


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quote:
Originally posted by The Evil Spam Gamgee:
I'd have thought that the colour which stands out most is the one to which the human eye is most sensitive, namely green...

No. Just because the eye is most sensitive to green, it's sort of a 'default colour', the one the eye has to do 'less hard' to see; red stands out more because is more 'aggresive' to the eye...

Jaime

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"Everyone has problems. They only vary in design" - Mama Duck


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dilbert
The Red and the Green Stamps


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quote:
Originally posted by Uncle Bubba:

In Texas they're horizontal with red on the left.

Confusing? Sure, but it's Texas. It's the standard Texas location.

Uncle "not mounted drag strip style." Bubba


Yes, but they are mounted standard for sideways lights. It's still a standard, there just happens to be 2.


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Finite Fourier Alchemy
Markdown, the Herald Angels Sing


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quote:
Originally posted by BlueRose:
Blue "red means stop, green means go, yellow means go very fast--anyone know which movie that line's from?" Rose

Starman, of course.

Do I get a cookie?

Alchemy

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Thinking about New England / missing old Japan


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dcmoore
The Red and the Green Stamps


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Slightly OT: I once got a chance to take a tour of a power plant. The plant control room was filled with little lights indicating the status of various pieces of equipment. I thought they must be in deep sh*t here, because 90 percent of the lights were red.

I later learned that red indicated the equipment was "hot" meaning that is was online and working. Green indicated "cold" meaning that piece of equipment was not in use.
Newer control rooms use computer consoles rather than panels of lights.


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davepawson
The Red and the Green Stamps


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quote:
Originally posted by BlueRose:
Blue "red means stop, green means go, yellow means go very fast--anyone know which movie that line's from?" Rose


Starman. Love that line.


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Ewok
The Red and the Green Stamps


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quote:
It's still a standard....
That's the great thing about standards: there are so many to choose from.

E "wanna play cowboys and endians?" wok


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