Night vision technology allows militaries to see and operate in low light conditions. This gives them a critical advantage for night time maneuvers and missions. But what color do they see through night vision goggles and scopes? Understanding the colors and imaging of night vision reveals how this tech works and its capabilities.
How Night Vision Works
Night vision works by amplifying existing ambient light instead of relying on an infrared illuminator. A photocathode tube converts the photons into electrons. These get amplified thousands of times by an electrical and chemical process. The electrons then hit a phosphor screen, which emits visible light that the user can see through the eyepiece.
This intensification process basically amplifies the natural light to brighten the scene. As a result, night vision displays imagery in the various shades of green. This is because the phosphor screen used emits a green glow when excited by the intensified electrons. Other phosphor colors are possible, but green has proven most effective for human vision.
Reasons for Green Night Vision
There are a few reasons why green is the standard color for night vision devices:
- The human eye can differentiate more shades of green than other colors. This allows for more detail in the intensified night vision image.
- Green phosphor screens require less energy to get bright. This improves battery life for portable night vision devices.
- The green light is easier on the eyes during extended viewing in low light conditions. Other colors like red can strain the eyes faster.
Additionally, green night vision goggles blend in better for military use than brightly colored ones would. Overall, green enables a good balance of visual detail, energy efficiency, eye comfort, and stealthiness.
Shades of Green
Military night vision devices display imagery in shades of green, but it is not just a solid green color. The level of green depends on the amount of ambient light available. Brighter areas appear more whitish green while dark areas seem deeper green.
This range of shades allows the user to see objects, terrain features, people, animals, and other details that would normally be hidden in the darkness. The different green hues help the eye pick up on contours, shapes, and depth perception.
Night Vision Generations
Not all night vision goggles produce the same quality green imaging. There are generational differences based on technological capabilities:
| Generation | Color Characteristics |
|---|---|
| Generation 1 | Very dark green imaging, limited details visible |
| Generation 2 | Improved green imaging with moderate detail |
| Generation 3 | Very good resolution green imaging |
| Generation 4 | Black and white or color night vision |
The higher generation numbers have better light amplification and resolution. This allows more shades of green and more discernable details to be visible to the user. Generation 4 can go beyond green imaging to black and white or even full color night vision.
Thermal Vision
In addition to night vision goggles, militaries also employ thermal imaging systems. These detect heat energy (infrared radiation) rather than amplifying visible light. Thermal vision displays a black and white heat signature map, not green hues.
Since thermal systems don’t need any ambient light, they can be used day or night. But they have less visual detail than night vision and cannot see through glass. Thermal is better for spotting personnel and vehicles based on their heat against the background.
Color Day Vision Options
During daylight conditions, militaries can equip full color optics and sights. These include:
- Rifle scopes and spotting scopes
- Binoculars
- Camera systems with telephoto lenses
- Targeting systems and laser rangefinders
Color day optics provide the full visible color spectrum and maximum visual detail. But full color imaging requires a lot of light, so it is not workable for low light night vision. The night vision green hues allow effective albeit monochromatic viewing in dark environments.
Differences in Color Perception
The specific shades of green visible through night vision depend somewhat on the user’s own vision and perception. Colorblind people may see the imagery differently. Anyone’s ability to discern small details and depths at night relies on their visual acuity and experience.
Younger people tend to have better night vision due to their eyes letting in more light. Younger also means less likelihood of cataracts, glaucoma, and other age-related eye issues. But wisdom and familiarity can compensate for poorer night vision. So veteran soldiers may interpret the imagery well even with older eyes.
Effect of Weather Conditions
Weather conditions also affect how night vision colors appear. Some examples:
- Clear nights – More stars/moonlight means lighter green hues visible
- Overcast/foggy – Softer green tint due to diffused light
- Rain/snow – Flatter darker green shades visible
- Smoke/dust – Degraded imagery with greyish or brownish greens
The amplifying capabilities of night vision are limited by the available natural light. Overcast, precipitation, and air quality conditions can reduce visible detail and coloration. But night vision still outperforms unaided dark adapted eyesight in these conditions.
Improving Color Perception at Night
There are some techniques soldiers can use to enhance the color details they perceive through night vision equipment:
- Adjust eyepiece focus for sharpest image
- Position gear for best light gathering
- Scan slowly to discern detail
- Close one eye when possible to devote maximal vision to night optics
- Train in daytime to learn colored details that are hard to see at night
Militaries also constantly test next generation night vision technologies to improve light amplification, resolution, and color quality. But the classic green hues will likely persist for optimal night vision capability balanced against other constraints like cost, size, weight, and power usage.
Conclusion
The green-cast imagery of night vision may seem strange compared to daytime color perception. But the shades of green effectively render nightscapes and details visible based on available light. Military development has optimized night vision systems for the green color scheme balanced against factors like visual acuity, battery drain, and stealthiness. So green remains the standard color for tactical night vision equipment and its lifesaving capabilities.