Keld Helmer Petersen - A danish Photographer who focused on shapes and kept his photographs very minimal. Some of his work uses very high contrasts. This moves the focus to the shapes and structures in each photo and strips away all the tones and shadows that a camera would usually capture. 

I used this technique on the images below by using Photoshop. I used 'threshold' and changed the levels of black and white that you could see in the image. I then inverted the image to see the opposite of the images. I also added colour instead of black for a similar effect however it looks more like to pop art: