there may be various ‘proper’ names for this type of photography; but i enjoy calling it
having one object in color against a b&w background catches the eye.
it makes this photo stand out amongst a world of constant color photography.
b&w photos were once all that existed in photography, at the beginning.
when color was introduced, everyone wanted something new in their photos.
since the world has been deluged with color photography, photographers everywhere are looking for something new; something different; something that will catch the eye of a passing observer and be more memorable.