There are variety of industrial and scientific applications where noncontact flow measurement through opaque walls or in opaque liquids is desirable.

A second high contrast copy is then made from the first, rendering the backing clear and the foreground opaque (fig.

First, a print from the original negative is made on high contrast film, which records the backing as opaque and the foreground subject as clear (fig.

The transparent façade is a unique design feature, because most buildings have only a single façade using highly reflective glass to lower heat absorption, but the Shanghai Tower's double layer of glass eliminates the need for either layer to be opaqued.