Blue72
Flashlight Enthusiast
- Joined
- Aug 24, 2007
- Messages
- 1,138
anyone know how many lumensfrom a red light you can use before ruining your scotopic vision at night
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anyone know how many lumens you can use before ruining your scotopic vision at night
The maximum amount of luminance that can support scotopic night vision is 10^-2 cd/m^2.
It's very comlicated to relate luminance to luminous flux, unless the environment is a uniform sphere. But if we assume that the source is located inside a 10m sphere, and the light source emits uniform light of 30-degree divergence, then:
Illuminated area = 1256/12 = 104m^2
104m^2/10^-2 Cd/m^2 = 1.04Cd
1.04/4.67 = 0.22 lumens
Thus, if you're located inside a sphere with a 10m radius, and use a floody 30-degree flashlight, the maximum amount of light you could use, without disrupting your scotopic vision, would be 0.22 lumens.
Is this regarding white light or red light, thanks
Well, white light implies a broad-spectrum emission between roughly 400nm and 700nm. LED-based white light isn't a simple function, because it's bimodal (in its current iteration), and only incadescent lights cover all wavelengths (albeit not equally either). The white LEDs have 2 phosphors, one that has a narrow short-wavelength peak, and a broader long-wavelength peak. I wouldn't be able to give you exact figures, because I lack the mathematical training to do it.Cool info! I've always been interested in learning about the relationship between LED color and night vision.
Meuge, do you have figures for other LED colors (blue, green, Y/G, etc.)?
Even if you use a "red" with a wavelength longer than rod sensitivity (640 nm) there is the issue of 'cone burn in'. Orange-reds and true-reds are so hard to see with that many are tempted to use them so brightly that an afterimage may be burnt into the cones that may completely overpower the dim image from the rods. So it's very easy to use a red light and preserve your scotopic vision and render it totally useless at the same time.That would be white light. At 600nm, the rods are almost 10X less sensitive, thus you could probably put out 10X more lumens and still retain your scotopic vision.
Surprisingly, (to me, at least) Dark Adapted Vision is still a controversial subject even in the 21st century. Searching around will show that this may be pursued by following any number of completely different strategies -- all of them having merit to one degree or another.So what lights are out there that work to preserve scotopic vision.
So what lights are out there that work to preserve scotopic vision.
You won't be able to see anything with low intensity red because you have zero scoptopic sensitivity there -- it takes a lot of red light before you can even see with it at all. I find red flashlights actually create a "tunnel vision" effect for this reasons -- with a red photon light in the dark, I can ONLY see things that are directly lit up in the hotspot, and nothing else. If I do a ceiling bounce with even a very bright red LED, it becomes essentially useless. On the other hand, if I ceiling-bounce a much dimmer green or white LED I can generally see the whole room clearly.Maybe the question should be, how much lux from a red light can I use before I ruin my scotopic vision? One lumen of red light spread out in a wide pattern may be just right, but that same one lumen collimated into a bright spot might ruin our night vision.
I've read that many game animals can not see green and some lights are advertized that way. I've observed that rats can't see red light.this light will be used for hiking at night outdoors and observing nightlife