Lumen prints

I have recently been looking at and trying my hand at lumen prints. Basically, a Lumen print is a photogram resulting from direct contact between a chosen object and black&white photographic paper which is then exposed to the sun for a fairly long period of time ( usually over an hour).As with cyanotypes, I think there's a certain quality to botanical contact prints that cannot easily be replicated by other means. I speak of the softness of outline and " ghosting" from elements that are not in direct contact with the paper.
This can imbue the image with a sense of hovering between states......between presence and absence.....between substance and spirit.