Why can't you see very well when you first go into a darkened room like a movie theater? When you first enter the movie theater, the cones in your retina are working and the rods are not yet activated. Cones need a lot of light to work properly; rods need less light to work, but they need about 7-10 minutes to take over for the cones. After 7-10 minutes in the dark, the rods do work, but you cannot see colors very well because the rods do not provide any color information. The cones, which do provide color information, need more light, but do not work well in the dark. After the movie is over and you leave the theater, everything looks very bright and it is hard to see for a minute or two. This is because the rods become "saturated" and stop working in these bright conditions. It takes a few minutes for the cones to begin to function again, and for normal vision to be restored.
