Black Scene White Subject

As discussed: When you have a black scene, the in-camera metering tries to find the proper white balance and of course... cannot.

Example:

The tea cup/saucer and shells in this picture are actually white.

You can adjust the white balance (Manual).

Or - as shown. You can adjust your subject into a greyscale image later in Photoshop.

The result... one of the best pictures I took. (cropped of course).