Many headlamps and flashlights come with a red light or lens option. Have you ever wondered why that is? Manufacturers, after all, are not going to spend time and money designing a feature on their products for nothing! In this post, we will discuss the purpose of the red light option/button on your headlamp or flashlight and how you can use it to your advantage in many activities.
What is the red light used for on a headlamp? Primarily, the red light is used to preserve your night vision while still allowing you to see in complete darkness. Red light also preserves your stealth which can be extremely useful in tactical environments or situations where you do not want to bother others.
Red light is used in dark rooms for photography, military missions, submarines, ships, and anywhere that needs enough light for humans to get around or operate in without giving location away as easily or potentially affecting a process (photography) as with white light! As a veteran owned site, we have our fair share of experience using a red light in the many facets of training administered to soldiers.
Why does the military use red light? The military has, arguably, the most uses for red light as it can help preserve stealth, eyesight, read documents and maps and navigate through the most remote of terrain all while being in pitch black darkness and not easily seen by the enemy. These benefits translate directly to the civilian world in which we can find ourselves out for a hike late in the afternoon, reading an astronomy map, doing nighttime photography, hunting, and going for a run to name a few.
Pros and Cons of A Red Light
If you are the type of person that enjoys information when it gets to the point, we created a list of pros and cons to red light. Following the lists below you can read more in-depth content on the specific uses, science, and applications for red light on headlamps or flashlights.
The Good
The red light on a headlamp is good for:
- Using in a small dark space where there may be others such as a tent in that you won’t disturb their eyes
- Using your peripherals at night while illuminating your path
- Providing a source of light from which your eyes can quickly adjust when off
- Keeping insects less interested in being around you
- Safety: most headlamps come with a strobe mode for the red light and this color of light, as you know, is used to quickly grab others’ attention such as in stoplights, cars, bicycles and so on.
The Bad
The red light on a headlamp is bad for:
- Most things unless reading a map or document IF IT HAS FLOOD BEAM. Spot beams are great in a red light because they allow you to see farther away. Flood beams will keep things covered in close up applications.
- Illuminating a large area because of its characteristics making it a short-range light
- Combining with a white light. If you are in a group and are the only one using red light this is a good time to give into peer pressure as your light is rendered useless thanks to the mechanics of your eyes
- Hunting at night. Green light is superior for this activity due to, again, the way our eyes receive color and light
The Uses For A Red Light
Hiking
Exploring the untamed wilderness (better known as hiking) is amazing in the daytime but can easily turn into a deadly experience at night if you get lost. Having a map will solve that but what do you do when there’s no light to read it? If you want to preserve your night vision you use a red light! Using a red light, however, can wash out any red colors in the map and make it, once again, useless. If you do not have a red-light readable map you can always use your headlamp’s white light BUT KEEP IT AS DIM AS POSSIBLE. If you do get yourself a red-light map then you can enjoy your red light feature as your heart desires.
Hunting
Hunting at night can be achieved by moving around with a red light as well. Animals’ perception of a red light is not the same as humans. You might be wondering what the point of using a colored light instead of a white light while moving towards your pray is: animals will still be able to see light, but because red light is less intense, animals are less likely to be startled.
Photography
When it comes to photography in the night there are two sides to look at regarding the red light from your headlamp. If you are moving around in the dark to find your next subject, you should use the red light to preserve your night vision as much as possible. If you are taking photos and there are people around using red light, the light WILL come into your photos and be easily seen. A camera does not work like your eyes.
Running
Running is a pastime that divides the world. Some of us would do it only if our life depended on it while others’ lives consist of logging dozens of miles a week for fun and health. Sometimes, especially in the winter, we can find that by the time we get off work it’s too dark to go for a run and the hobby quickly becomes a distant memory. Running with a headlamp can help you maintain your fitness and mileage log. By now you probably understand why you would not want to use white light in an area that is super dark. If you are running in a somewhat lit street you might be able to get away with using white light to light the path directly in front of you. Running anywhere not well lit? Use a red light with a SPOT beam to keep your ankles unbroken! Running with a white light can also cause pretty bad tunnel vision after about 20-30 minutes in our experience.
The Science Of Red Light
Human Eyes
Human eyes, obviously, are sensitive to light and can differentiate between millions of colors. The light our eyes can detect ranges between the 400-700nm wavelengths. Cone cells in the eye detect color while rod cells detect light intensity. Your vision in the daylight (cone vision) is used for seeing colors. Your night vision (rod vision) is used for detecting movement and dim light.
Our eyes have many times more rods than cones (120 million rods and 6 million cones) and yet here we are learning about a device to help us see at night because our feeble human eyes don’t cut it. The rods dominate the peripheral vision and that is why you can see dimmer objects within your peripherals.
Rods respond very little to red light (We’re moving to the knowledge you came for!) which is why we see everything in a gray scale at night.
Adjusting Your Eyes To The Dark
How long does it take to your eyes to adjust to the dark? Your eyes can take up to a half-hour to attain night vision and since rods are not sensitive to red, the red light on a headlamp does not ruin your night vision like white light. Red light, in essence, allows your eyes to see in the dark quite quickly after turning off the light because your rods are being used and they are not impacted by it but your cones can see it and when it’s gone they are not used to see at night. Have you ever wondered why night vision is green?
Night Vision Goggles
Why are night vision goggles green? One cool fact about night vision goggles is that they are green because our eyes are more sensitive to green light. Night vision goggles work by basically multiplying the photons and turning them into electrons. Electrons do not have color like photons and so because our eyes see green more easily, the color in night vision goggles is made green to allow us to more easily identify objects while using it.
Should I Get A Lamp With A Red Light?
If you often find yourself in situations where you are in the dark and on the move, or where you want to take in what is around you in the darkness, a red light will be an amazing resource for you as it can be of great help without much hindrance.