Which radiation is used to take photography in dark?

there is always a bit of light at all times unless i geuss something is specifically designed to let in no light, but the camera has a speed at which it opens and closes it shutter which lets the light go in to affect the film kept on the inside. so the longer you leave that shutter open the longer the light has to go in to effect the film. so since there is less light you have to leave the shutter open long enough for the film to be effected by the light, which is why you need a tripod when taking long photos cause its easy to make the photo blurry. if there is a lot of light you only have to open the shutter for a fraction of a section. unlike in some dark photos you have to open for even a few minutes.