What is the role of adjustable lighting in VT?

• A. To permanently fix lighting for all surfaces.
• B. To optimize visibility for different surface conditions, reduce glare, and maximize contrast for defect detection.
• C. To brighten the entire workspace.
• D. To replace the need for other NDT methods.

Answer: (B)

In visual testing, lighting is used to reveal surface features by the way light interacts with the surface. Adjustable lighting lets you change direction, angle, and intensity to bring out defects under different surface conditions. By shining light at a shallow angle, you cast shadows along edges and within cracks, making flaws stand out more clearly. Grazing illumination highlights fine surface roughness and texture, while diffused light reduces harsh reflections on shiny areas so you don’t drown out fine details. The aim is to maximize the contrast between a defect and the surrounding material while minimizing glare and glare-induced masking. This adaptability is essential because different materials and finishes respond differently to light, so a single fixed setup can miss defects or misrepresent surface condition. Simply increasing overall brightness doesn’t guarantee better visibility and can wash out features or create new glare. Lighting complements, rather than replaces, other inspection methods.