What color should my dog’s night light be?
November 5, 2022 1:35 AM Subscribe
Does the color of light affect how useful it is for navigating our otherwise dark bedroom?
We have stairs that our senior dog uses to get up and down off the bed. She often likes to roam the house at night (midnight snacks, of course) and was having difficulty seeing the stairs to get back on the bed. This situation has been much improved by adding a motion activated hue light.
When I added the hue light, I set it to a red color, as that’s what I preferred. This seems to serve the intended purpose. But today I started wondering whether a different color would be better for Penny to see by. I did some googling and read the basics about rods and cones, and saw that dogs don’t have red cones. But does that impact how much light they can see at that spectrum? Or do they just not perceive the red color?
We have stairs that our senior dog uses to get up and down off the bed. She often likes to roam the house at night (midnight snacks, of course) and was having difficulty seeing the stairs to get back on the bed. This situation has been much improved by adding a motion activated hue light.
When I added the hue light, I set it to a red color, as that’s what I preferred. This seems to serve the intended purpose. But today I started wondering whether a different color would be better for Penny to see by. I did some googling and read the basics about rods and cones, and saw that dogs don’t have red cones. But does that impact how much light they can see at that spectrum? Or do they just not perceive the red color?
Some more information about dog vision here. Dogs are effectively red-green colour blind as they don’t have separate receptors for those colours like we do. So red light, however bright, to differentiate greenish stairs, won’t work for them. Better to go with something yellow, white or blueish. On the other hand dogs vision is more sensitive than ours - so it need not be a very bright light.
posted by rongorongo at 3:03 AM on November 5, 2022 [3 favorites]
posted by rongorongo at 3:03 AM on November 5, 2022 [3 favorites]
In dim settings, humans rely far more on their rod cells, which are orders of magnitude more sensitive than cone cells, but don't distinguish wavelength (that is, color). You can observe this yourself in the difficulty of distinguishing colors at night or in dark rooms. I haven't dug into the research to know the specific differences between humans and dogs when it comes to this phenomenon, but I'm pretty confident the story is the same. Per Wikipedia:
posted by Cogito at 1:16 PM on November 5, 2022 [1 favorite]
As crepuscular hunters, dogs often rely on their vision in low light situations: They have very large pupils, a high density of rods in the fovea, an increased flicker rate, and a tapetum lucidum.In other words, the color of the light isn't very relevant in low light scenarios for humans or dogs, and since dogs tend to do better in low light than humans, I'd choose the color that you prefer.
posted by Cogito at 1:16 PM on November 5, 2022 [1 favorite]
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posted by dhruva at 1:57 AM on November 5, 2022 [1 favorite]