Digital discovery

This photo came out of the camera looking totally black. I used Levels, in which the histogram showed some acitivity on the far left and a vast blank space on the right - even less activity than this, in fact about a tenth as much, all over on the far left -

By taking the "white" pointer on the right and sliding it towards the "black" pointer on the left, the image was revealed ... not very well, but there's definitely something there.

What is it, you may wonder. It's shadows on a bedroom wall, cast from the street lights outside. Usually I don't see them because I don't put my glasses on when getting up in the dark middle of the night, but in winter it's dark enough in the morning for such shadows still to be there. I've used this bedroom for nearly 20 years and (incredibly) not noticed this phenomenon before - the tree branches waving in the wind in one triangle, the fainter shadow of the other. Triangles because of the sloping roof and dormer window. They are orangey because of the sodium street lights, but sometimes a car turns a corner and its lights cast a bluish shadow, moving upwards at left and onto the ceiling, then it's gone.

They do say digital cameras can be used without flash in low light conditions.