This is an ortholith, commonly reffered to as an "ortho". An ortho is made by placing a negative down onto ortho film and then exposing that to light, thus making a 35mm positive. That process is repeated to make a negative of the image. By the time that this is done again, there are no shades of grey. Only pure blacks and whites. This negative is then used to shoot a positve onto normal paper like any normal print.