These drawings are done with covering a stretched canvas with multiple layers of charcoal and erasing the highlights of the image. Because the white canvas is revealed through the charcoal, it is see-through and allows you to shine a light through.
You can choose to display it as a standard black and white image or install a light strip on the back of the canvas (warm or cool lighting gives a different atmosphere to the drawings).
All the artworks are finished with multiple layers of fixative.