Quote Originally Posted by X. Phot. View Post
Just saw this in Popular Science Feb '37 - To leave a white signature, simply write it on the photographic paper with a soft lead pencil prior to exposure. The pencil lead will wash out during development.

I haven't tested this yet. But it sounds reasonable. I can imagine that some papers won't take to pencil lead very well.
but x.phot ...
is there an article on leaving a BLACK signature ?
white signatures are easy