Desaturate and Invert

The trees and the branches you have photographed will be green or brown in colour. As we only want black and white tones to achieve the Sabattier effect, we need to desaturate the image. Select Image > Adjustments > Desaturate, then select Image > Adjustments > Invert to reverse all of the tones. As we are only using black and white, they will turn into the opposite of each other.