Why does it take a while to see?

Inside your eyes are lots of tiny light-catchers. Some work best in bright light and see colours. Others, called rods, can work with just a glimmer, but they need time to get ready. After about twenty minutes in the dark, your rods are doing their very best.

Why do colours look grey in the dark?

In very dim light, your rods do most of the seeing. They're brilliant at catching a glimmer, but they can't tell colours apart. They see in black, white and shades of grey. So at night, your red pyjamas look grey until the light comes back on.

Why can't I see when the light goes off?

Fuzz answers for ages 4–11, then goes 2 steps deeper each time a child asks why.

Fuzz says

In the middle of each eye is a little black circle called your pupil. It's an opening that lets light in. When the light goes off, your pupils open wider, so they can catch every bit of light there is. Then, slowly, your room starts to come back.

For ages 4–7

Checked against Your eyes (KidsHealth)
Why does it take a while to see?

Inside your eyes are lots of tiny light-catchers. Some work best in bright light and see colours. Others, called rods, can work with just a glimmer, but they need time to get ready. After about twenty minutes in the dark, your rods are doing their very best.

For ages 6–9

Checked against How do my eyes adjust to the dark? (The Conversation)
Why do colours look grey in the dark?

In very dim light, your rods do most of the seeing. They're brilliant at catching a glimmer, but they can't tell colours apart. They see in black, white and shades of grey. So at night, your red pyjamas look grey until the light comes back on.

For ages 8–11

Checked against Your eyes (KidsHealth)