Dark Field Lights and When to Use Them

Dark field illumination can be used to highlight edges, for example surface irregularities such as scratches or engravings.

Unlike normal ring lights, this type of light does not illuminate the object directly; this way the light reflected into the camera is mainly from the edges of surface features.

In this respect, it is similar to beam illumination in a dark field arrangement, but the key difference is that dark field illumination does not focus on any particular direction.

Application example: edge detection, inspection of engravings, inspecting metal surfaces for damage or stains, and reading laser markings.