Shades of Grey or to the likeing.

black and white photography is the use of light, playing with lights and darks of a form and using them to your advantage to get a great exposure. In making prints you take the negatives- and use the light to either make those shadows and bright spots subdued or stronger making a more dynamic picture. despite the connotations that grey has, photography takes it and turns it around. Obviously with the issues that it can be done badly and the photo would fit into the traditional blah, black and white photo. But with the right lighting and combinations of shadows, an image can be brought out.
Even with color photography, the general idea still applies, lights and darks but now you also work with hues and tones to bring another level of image. Its really the lights and darks that change and modify the photograph and adjust the feel of it. with black and white, it leaves more to the imagination and allows for more expansion of the image.