On set, which tool helps confirm white balance when color temperature varies?

• A. Color checker chart.
• B. Digital camera.
• C. Diffuser.
• D. Gray card.

Answer: (D)

White balance needs a neutral reference to remove color casts from different lighting. A gray card provides a known neutral gray surface (about 18% reflectance). By photographing it under the current lighting, you can set a custom white balance in-camera or in post-processing, giving the camera a consistent reference to compute color temperature and tint. This makes WB reliable as color temperature varies across scenes. A color checker chart can help with overall color accuracy later, but its primary use is broader color profiling rather than immediate WB confirmation. A diffuser changes light quality, not a reference for color, and a digital camera is the tool itself, not the reference you use to set WB.