PhotoFun

In the age of digital photography, there is no real original photo but only luminance data. Most cameras will present an optimized jpeg as the photo, but that is a convenience.

Photobooth Jpeg:

Greyscale ie all the shades of luminance available:

Straightened, cropped, and adjusted. The available luminance is always the same, but greyscale with filters in various combinations will bring out different aspects:

The controls on PhotoBooth: