Choose the right tool for the right job. Listed below are brief descriptions of the most common types of lighting.

Back lighting: Commonly used for finding holes and taking dimensional measurements of objects (webs). Bright back lighting can penetrate opaque webs thus highlighting specs and blemishes within the web as dark spots.
Front lighting: Commonly used for applications where features on the surface of the object (web) are to be inspected. It is a simple concept where the lights illuminate the object from the front. Typically the lights are angled at 45 degrees shining down from the side with the camera looking straight down at the object. This technique is best used on surfaces that are not too reflective.
Diffuse Lighting: Commonly used for inspecting very reflective and curved surfaces and for detecting the presence of features on polished components. Polarizing filters also allow unwanted reflections to be dramatically reduced in intensity.
Structured Light: Commonly used to illuminate objects in order to extract depth information where other methods are impractical. Typically this involves a laser light source emitting a line or lines of light which, when projected on the three dimensional part, leaves a profile of it from which to gain data.
Ring Lighting: Commonly used when inspecting circular objects, small objects, or small areas of large objects. This technique provides very even illumination around the object.

Fiber Optic Lighting: Commonly used for small space constraint and small object illumination.
Low Angle Lighting: Commonly used for highlighting small surface features and textures where the features will appear bright against a dark background. In this technique, the light source shines from the side at a very low angle where the light glances off the object. It is important in this scenario to maintain a constant angle from light source to object for consistent and accurate results.