What Color .......
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blackice
Contributor
I have heard that blue and green are the most visible in the water, not sure if it's got to do with different wave lengths or not.
I have also never see a blue or green light under water only red, or if you could glow sticks then I've seen red, purple ... I remember that the red was more noticeable than the purple.
But also the red is more an alarming colour.
I'm sure there are others that have extensive knowledge about this topic, be interested on what works.
=-)
I have also never see a blue or green light under water only red, or if you could glow sticks then I've seen red, purple ... I remember that the red was more noticeable than the purple.
But also the red is more an alarming colour.
I'm sure there are others that have extensive knowledge about this topic, be interested on what works.
=-)
The eye is most sensitive to green light (a major reason that night vision goggles use a green display) and it will be distinguishable as a green light farther through water where reds are quickly absorbed.
BradfordNC
Contributor
DA hit it right on.
green is the easiest and most noticeable for your eyes to pick up.
it is not only one of the reasons, it is THE reason night vision devices use green displays.
and it is the best one for surface use as well.
doing search and rescue tests, a green laser on the surface can be seen from an aircraft over 50 miles away.
green is the easiest and most noticeable for your eyes to pick up.
it is not only one of the reasons, it is THE reason night vision devices use green displays.
and it is the best one for surface use as well.
doing search and rescue tests, a green laser on the surface can be seen from an aircraft over 50 miles away.
So I got a question. If the coast guard is out searching for you cuz you are lost at sea, and they are using the night vision goggles to try and locate you, how will they see your green light thru their green goggles?
msedivingdoc
Guest
NVG's or night vision goggles work by gathering available light particles and then concentrating them on a screen for the person to see. Any light, even green would give the same effect. Of course white or ambiant light will give more available light.
vicky
Guest
which respond to Green, Red and Blue (photon hit these cells and they react by generating electrical pulses to the brain, thus transforming light energy to chemical and electrical energy). Color perception is the result of a combination of the response of these cells to the light that hits them. There other cells too, sensitive to contours (which give us our poor, limited night vision but they do the job- sometimes it is better to rely on them rather than using a poor light. These cells are not rellevant in our discussion).
In humans, the green cells have a better responsivity than the blue and red ones. Therefore, if we put two light sources of the same intensity and energy, say a red laser and a green laser, we will "see better' or brighter the green one.
However, human vision is not all about RGB sensitivy. Vision and color perception depends a lot on contrast, background, relfection, luminosity etc. etc. For example, emergency crafts and life-saving jackets are usually in red, orange or yellow and not in green. With the sea's blue background, one will see better red and not green. On land, one will see better green agains brown, rahter than red against brown. Maybe this property was developed in humans by evolution, so we can better find food sources from far distances (Most plants are green, most grounf is brown)??
In night googles ( to answer your question), the green display is not color-imaging, it is photon-imaging. The image does not represent any type of colors: it represents the amount of light (generated from the stars and moon) being reflected from the objects you're looking at. Of course, if one lights a torch or a cigarette you'll see them very well with night googles, which are light-sensitive
The display is in shades of green for convenience only.
In humans, the green cells have a better responsivity than the blue and red ones. Therefore, if we put two light sources of the same intensity and energy, say a red laser and a green laser, we will "see better' or brighter the green one.
However, human vision is not all about RGB sensitivy. Vision and color perception depends a lot on contrast, background, relfection, luminosity etc. etc. For example, emergency crafts and life-saving jackets are usually in red, orange or yellow and not in green. With the sea's blue background, one will see better red and not green. On land, one will see better green agains brown, rahter than red against brown. Maybe this property was developed in humans by evolution, so we can better find food sources from far distances (Most plants are green, most grounf is brown)??
In night googles ( to answer your question), the green display is not color-imaging, it is photon-imaging. The image does not represent any type of colors: it represents the amount of light (generated from the stars and moon) being reflected from the objects you're looking at. Of course, if one lights a torch or a cigarette you'll see them very well with night googles, which are light-sensitive
The display is in shades of green for convenience only.
The human eye has receptors for red, green and yellow. When you talk primary colors there is a big difference between the additive color mixing we are taught in elementary school art classes and the subtractive color mixing that occurs in your eye.
It has been a long time since I had any kinds of perceptual psych class, but in general you have red receptors and you have green/ yellow receptors. If a red receptor is activated it excretes a neurotransmitter that actually inhibits the green/yellow receptors around it. This aides the eye in it's ability to accenuate lines, and this is ability is why camoflage patterns and other means to break up lines and readily discernable sillouettes are used.
You may also note how under some light less than full light conditions (a setting sun poking under an overcast, etc) that greens (and to some extent yellows) seem much brighter and almost glow. This is called the perkinje effect (not sure on the spelling) and results from a larger percentage of red light being filtered out allowing the eye to "see" more green and yellow light than it normally does due to the red receptors not inhibiting the firing of green/yellow receptors.
NVG's use green as the eye is most sensitive to it, (in large part due to the ability to use the heightened sensitivity of green receptors in the abscence of red light) and this allows lower levels of brightness to be used on the NVG display. Also green light at the correct wavelenght (like the correct wavelenght of red light) will allow your eyes to continue to be dark adapted so that you can see better in low light conditions when you remove your NVG's.
It has been a long time since I had any kinds of perceptual psych class, but in general you have red receptors and you have green/ yellow receptors. If a red receptor is activated it excretes a neurotransmitter that actually inhibits the green/yellow receptors around it. This aides the eye in it's ability to accenuate lines, and this is ability is why camoflage patterns and other means to break up lines and readily discernable sillouettes are used.
You may also note how under some light less than full light conditions (a setting sun poking under an overcast, etc) that greens (and to some extent yellows) seem much brighter and almost glow. This is called the perkinje effect (not sure on the spelling) and results from a larger percentage of red light being filtered out allowing the eye to "see" more green and yellow light than it normally does due to the red receptors not inhibiting the firing of green/yellow receptors.
NVG's use green as the eye is most sensitive to it, (in large part due to the ability to use the heightened sensitivity of green receptors in the abscence of red light) and this allows lower levels of brightness to be used on the NVG display. Also green light at the correct wavelenght (like the correct wavelenght of red light) will allow your eyes to continue to be dark adapted so that you can see better in low light conditions when you remove your NVG's.
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