BEFORE READING, CONSIDER:
My intentions are not to create a race of underground elves similar to the Drow/Mori or Mrowi in a combined form. I use the example of underground plenty, but it could also mean justification for being nocturnal, or any other creative device you can think of. You're free to use your imagination to this enabler, not parameter.
With this I only declare that a dark elf's eye naturally adjusts to low light environments. With many dark elves living underground, this a logical and reasonable assentation to make.
The fact remains that there have been dark elves underground since Aegis. This fact cannot be ignored or swept away to achieve your own personal interpretation of a DE, nor can the fact that some lived above ground. (Thus you must find a bridge of sorts that enable both to be roleplayed. How the same person can see plainly in the day or be able to see in their cavern) Even if you do not agree that even a portion of dark elves live underground and are comfortable, you cannot deny previous roleplay sessions. The purpose of this lore is to create roleplay for those dark elves who do choose to live in a nocturnal sense or underground, they are going to be doing it anways. There is many many different ways to play a darkie, this does not conflict wit any at all(Nor do I intend for it to)
A surface dark elf and a cave dark elf (or a nocturnal dark elf)all answer the same question/situation I propose, yet they do it in different ways.
For people who have followed recent dark elf activities you would notice that dark elves have been living both on the surface and below ground, drawing from DEs from popular fiction such as Drow (altered to fit LOTC Lore of course) or TES dumner. For a race to be able to see clearly in a dim cavern, and enjoy the environment or walk on the surface along an other elf would mean a drastic changing in the eye from light to dark. Both of these roleplay forms should be encouraged and have been roleplayed out extensively on both ends, yet if you're going to be a cave darkie or a surface darkie there should some things to keep in mind. Yet first to understand how that might work in the context of how dark elves have been rped, we need to first understand how an eye works.
The Eye
As you can see from the diagram, light hits the lens and is focused into the pupil which is a small opening in the eye that allows the focused image to enter into the eye where it's processed by the brain. The pupil can expand and contract in order to allow more light in a dim area to come into the eye, giving a weak form of night-vision; however it takes a few seconds for it to expand and attract according to the environment. We have all experienced this after stepping out of a cinema, only to be blinding by the light outside. Your pupil at that current state is taking in too much light, thus you squint or close your eyes.
The Dark Elf Eye
There is no special cell group that would make a dark elf be able to see in on both ends of a value spectrum, they all have a lens, iris, cornea, rods/cones, and ect. However, I would imagine that a DE can be rped in both scenarios with the ability of the pupil to contract to expand to an abnormally large state; however, to change from such drastic ends of a scale would call for temporary reparations of sort which I can best explain in this example
Mushroom farmer Khel lives beneath the earth in a small mushroom-farm with his family. The world around him, beneath the ground, he has enough sight in his cavern to fend off the local giant lizards and spiders yet regardless of these monsters,he enjoys it there. However, the evil High Prince demands he pay a fee for living on his subterranean land so he is forced to sell his wares at a surface market above his home. The dark elf would climb out of his cavern and emerge to the surface, only to find it's daylight outside. He would feel a strong pain in his eyes, as his hyper extended pupils take in a harmful amount of light. For days he may not be able to see because of this error. However, he may choose to emerge at night and allow the daylight to ease in and allow his eyes the proper time to adjust. When the day finally comes, his eyes have adjusted normally to his surroundings and he can sell his wares to pay his taxes to the evil high prince.
However, on his return home he finds he cannot see as well in the dark as he could before. So he must sit and wait and allow his vision to adjust slowly over time, before he returns to his wife and seven children(He is a dark elf after-all)
How would this effect roleplay?
A dark elf who has lived on the surface for a long period of time, cannot immediately jump into dark areas as his cave dweller friends could. He would have to wait a handful of minutes before he can see in the dark (Or just use a torch like his any other race), yet once the DE is able to see, he can see more clear than his fellow pale-skin adventurers.
A dark elf who has been living underground for a long time cannot just run straight into light, without causing serious damage to his eyes. He will need to slowly ease into it, perhaps arrive at night or cleverly use a mage to help him. Strong and sudden bursts of light would cause visual damage if it occurred within the confines of a cave darkie's domain.
If a dark elf has been underground for a long time, you would notice that his pupils are much larger than any other elf or human than you've ever seen. (As they need to be larger to take in more light)
New role-play opportunities as the light sensitive dark elf in the group of adventures must shamefully call out to his comrades as to ask them to wait, as he cannot see or he may be blinded. However, once he can see in the dark it's superior to the other's
A more visceral and realistic feeling to a people that are fantasy.
Weather or not you think dark elves should be living only underground or only on the surface, the fact remains that both have been rped out since Aegis. Rp that has already happened cannot be ignored or denied, it can only be further utilized. There are many ways to play a dark elf, and their physiology should allow for the diverse range of rp that a darkie can have.
Parameters of the low light vision
There must ALWAYS be a light source present in order for sight to be achieved, as sight is the reflection of light off of a surface and hitting your eye. So in areas of complete darkness, or magical darkness you will never be able to achieve sight.
Yet in areas of low-lightm such as underground or night, a dark elf will still achieve sight; however, it would not be the same in appearance if he were to see in daylight. It would look nothing like the detailed, modern night vision that we have today. In the very small areas of light, at relatively far distances (Let us say 50-100 meters for the example) you would be unable to discern details of a figure. It would appear as simply a colorless figure with a discernible shape yet no discernible detail. The closer the figure, the more detail you will find. A dark elf at night would see a brighter and more colorful night; however, no so dramatically that it appears as our interpretation of day.
Color in low light environments would be eradicated, unless adjacent to a light source. The further away from the light source, you receive less lower frequency light colors (Meaning first you lose red then orange, yellow, green, blue, and purple) The world in a low light environment would appear rather grey and bland, unless you were to bring the object next to a flame.
It's not unheard of for a dark elf to suffer from intense headaches or even migraine when their mind adjusts to rapid changes in light. The more often the dark elf puts itself to changes in light, the more likely he is to develop a headache or migraine.
Rate of Adjustment, clerification
The pupil of a dark elf can extend much further than a fellow elf or human can; however, there rate at which the pupil compensates for change is much slower. A dark elf stepping out of a cinema after two hours would have a strong blinding pain in his eyes. A dark elf who has been practicing clerical magic (which is bright, white lights) will have trouble adjusting to the dark immediately.
Again a surface dark elf and a cave dark elf are providing two different answers to the same question: How to avoid dramatic light changes. Even if such is subconscious.(IE some live above ground and often restrict themselves to that, while surface darkies do the same) Note that even if a dark elf has this low vision, in order to coup with their environment they already live in, it would be no different than the vision you have oocly. In mc you either see the person or don't, and dark elves don't get a magic ability to look through walls. Nothing ,in essence, has changed other than the ability to generate more rp
((PS, this was just some quick lore. If there are any questions or criticisms I will answer after my classes today))