As to the print, if you were going to do this, how would you do it?
You certainly would not scratch your negative if you wanted streaks of light rain!
If I had any sense (which I may or may not), I would not alter the picture on the negative at all. I would make an underlay of some sort for the neg. Black lines on a piece of glass or film would do it.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."
wildbill is correct. I'm in the Fx business. That's exactly how you do it. And it takes less wind that you would expect to get the rain to go sideways. A large fan from Home Depot and a black background would do the trick. Then all you need to key it, is Photoshop.
My first thought when I saw the photo was strings stretched across the set. Could also explain the "wind driven" effect. Both upturned corners of the kimono are quite close to a rain streak. Like I said, just a thought.