I don't know if it's just that I have better proprioception than most people, but I can 'see' my body, without color, when I close my eyes. From what I can tell, it has nothing to do with light. It's more to do with my body knowing where everything's at, and assembling that information in my mind as a 'visual' data.
This works no matter where the body part is. For instance, if I close my eyes and put my hand behind my back, I can still 'see' it.
Moreover, it works to a limited degree for anything I'm touching as well. I can 'see' the areas of the object I'm holding. If I've touched the entire object, my mind retains the shapes it felt, and displays the whole object (as it was when I felt those areas) as if I were seeing it with my eyes.
I hope this research goes somewhere. I'd like a scientific explanation for this phenomena.