Adjusting Your Eyes To The Dark
Techniques I learned through college astronomy courses will also work for ghost hunting in the dark. Your night vision will dramatically improve after about 10 minutes of being in the dark. You will be at your best night vision in about a half hour.
I have a hard time believing people who have just turned off their flashlights in a darkened hall, who claim that they see "shadow people" 50 yards away darting from room to room. Their eyes can not possibly be adjusted to the darkness to see that well. Maybe if you follow these steps it will help improve your night vision, so you can see better in the dark. If you must carry flashlights, be courteous and do not shine them in anyone's face or better yet, use a colored filter.
- Use your peripheral vision because it is more sensitive in low-light situations. The human eye has 'rod' cells and 'cone' cells on the retina, which is the sensory layer at the back of the eye. Rod cells and cone cells are distributed evenly throughout the retina except for the fovea, which is a small area on the back of the eye opposite the pupil. At the fovea, there are only cone cells. This is an important thing to know because the 'cone' cells are more proficient at color detection, whereas 'rod' cells are better for low light and detecting movement. Therefore, when trying to see in low light, try not to look directly at the places you are trying to see. By using your peripheral vision you are using more rod cells, which work much better in low light. This takes a great deal of practice for most people.
- Keep your eyes adjusted for the dark. If you're in a lighted area and know you're going to be going into a dark area, close your eyes tightly, or at least squint your eyelids before entering the dark to give your eyes a chance to adjust. If you can't close both eyes, close one or place a hand over one. This works well when driving into tunnels. Once you're in, avoid looking directly at any light source, no matter how dim you think it is. It takes longer to adjust back for the dark than it does for your eyes to adjust for the light you just looked at.
- Practice. This can be as simple as shutting out the lights in a room and closing all portals, allowing only the ambient light that slips in under the door.
- Scan, don't stare. If you look at something, or a place, in the dark for too long, your eyes will become less sensitive to what little light there is. If you scan your eyes back and forth over the area you are looking at, you will be using different areas of "rods" as described above, and you will be able to see details clearer.
- Protect your night vision. If you do need to use a light, having a colored lens over the light will help preserve your night vision. White light, containing all frequencies, from red all the way to violet (the visible light spectrum), will ruin your night vision the fastest. Red is favored when you need to recover quickly, green or blue-green should be used for acuity. Whatever light that is used, it's important to use as low intensity as possible.
Tips and Tricks
- For best vision, allow plenty of time to adjust to seeing in the dark. It typically takes about 20 to 30 minutes for your eyes to fully adjust to dark conditions
- Flashlights should be covered with red colored cellophane. You can even coat the flashlight lens with some red nail polish for a more permanent effect. Many stores also offer red LED flashlight that last a very long time.
- An illuminated watch dial can be a handy source of very-low-power light.
- Avoid looking directly at light sources while navigating in the dark. Even if you aren't looking at them directly, light sources close to your face will diminish night vision. For example, if you are smoking, the red/orange glow in front of you provides enough light to cause your pupils to contract, therefore killing your night vision. Similarly, you will not see much if you're wearing a miner's helmet with a light or carrying a flashlight (excluding what's illuminated by the beam of light itself, of course).
- Stargazing programs often have an option to make the screen red, because red does not affect your rod cells. So, you can look at red light forever and still see in the dark well.
- The fashionable eye patch worn by the pirates weren't always due to the loss of an eye. In fact, many pirates did it so that the one eye was good at seeing in the dark.
This information can also be found at: http://www.wikihow.com/See-in-the-Dark