Darkness can look like the darkest shadows, the darkest corner or people in low lit places at night. Shadows are just silhouettes created by blocking the light to a surface with an object in front of the light source. When it is night outside our ability to see at low visibility complicates our ability to see details. You can create objects in shadows, depth in shadows and attach shadows with the shadow blister effect. The shadow blister effect happens when two objects are casting a shadow in between a non-point light source and appear to be joining and expand in the penumbra part of the shadow before the umbra part of the shadow touch.
Anything that could help someone see anything recognizable is diminished greatly when there is no light. There are different ways one person can see the night. In twilight hours, in shadows or turning off the lights after certain hours.
As humans, we have very poor night vision to see things in the dark. Most other animals have better night vision than most humans in low lights. Darkness has no speed of light. The colour we see when we turn off the lights turns into a dark grey. We even have the name of the colour. Eigengrau, the colour of darkness after the lights are turned off. Our eyes are not that strong to see the colours and objects in front of us, therefore, they are converted to a singular shade of dark grey. There is a wide range of colours that we just can’t see.
Eigengrau is the colour of darkness. It goes by other names like intrinsic grey, dark light or brain grey. In German, it means own gray. In Dutch, it is spelt Eigenlicht with the same meaning. It’s the colour we see when light is absent. The name dates back to the 19th century. It was a term introduced by German psychologist, philosopher, physicist and the founder of psychophysics Gustav Theodor Fechner to determine the greys seen in perfect darkness.
A term is known as visual noise or background adaptation. Noise is defined as a random variation of brightness or colour information in an image. They are unwanted signals that are closely related to their audible acoustic noise, static. It is classified as a retinogenic phenomenon, a closed-eye hallucination. The colour can have variations of visibility. If Eigengrau was paired with black it would appear lighter. That’s because our brains prioritize contrast over colour representation. Contrast by definition is the difference of lumination and colour.
The Young-Helmholtz theory is the theory of trichromatic colour vision. This is about the photoreceptor cells in the eyes of humans and other primates to enable colour vision. The theory is from Thomas Young and Hermann von Helmholtz both from the 19th century. They proposed that we had three different types of receptors to be able to see colour. In 1802, Young suggested that the eye has several different eye photoreceptor cells that are sensitive to different wavelengths of light in his paper Observations of Vision. In the mid-1800s, Helmholtz expanded upon the theory that the cone receptors were short, midlength and long wavelengths to see and interpret colours.
Helmholtz conducted various experiments to see if his theory was correct. Participants would alter the amounts of three different wavelengths of light to do a colour match.
Some animals that have an excellent night vision range from being small animals, insects and birds. The common cat is probably the best urban visitor with night vision. Your cat has 25 rods per single cone in each eye beating our four-to-one ratio. This means the cat doesn’t have the best colour vision but can see one-eighth of the amount we would need to see at night. They also have long and narrow pupils for more light to enter their eyes and tapetum lucidum which reflects light around their eyes that they need less influence of light around them to see. It also makes their eyes look like they are glowing-in-the-dark.
Here’s a video of an owl with great night vision:
Some people cannot see in the dark at all in poor light. They are night blind. It is not a disease but a retina problem. Unless the person is myopic then it’s an optical issue. The five causes of night blindness would be from nearsightedness, certain medications, cataracts, retinitis pigmentosa and nutritional deficiencies.
Are you afraid of the dark?
Many people can be afraid of the dark. This could be attributed to anxiety or depression but it also can be from a lack of visual stimuli to see what is in front of them. The phobia is called nyctophobia which translates from Nyx the Greek word for night and phobia meaning fear. Other names for the fear are called scotophobia, myctophobia and achluophobia which means the fear of darkness also lygophobia which means the fear of being in dark places or darkness. Physical symptoms of being afraid of the dark according to Healthline.com would be trouble breathing, racing heart rate, chest tightness or pain, shaking, trembling, or tingling sensations, lightheadedness or dizziness, upset stomach, hot or cold flashes and sweating. Sometimes, it may be influenced by horror films and thrillers being too dark and spooky. Our imaginations can work against us and make something out of nothing. By having this phobia it can make it difficult to get a good long sleep at night since the person might get startled by noises at night.
But a little fear of the dark is good for us. Paying attention to your surroundings is a good self-defence when walking alone at night. Being uncomfortable in spooky situations is a good thing. Some people might fear being in the dark because they may not know what’s is there in front of them. Almost like being afraid of the unknown. This could be an evolutionary trait that could have been passed down through genetics.
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A Dictionary of Hallucinations – Jan Dirk Blom – pg 170 – 2009