Dual-Side 30cm Exposure Calibration Card

This 30 cm photographic calibration card features two purpose-built surfaces: an 18% neutral gray side calibrated to ISO-standard reflectance, and a pure white side formulated for neutral chromatic response. Both sides use non-reflective, pigment-stable matte coating to ensure long-term consistency and resistance to environmental wear. The gray side includes a laser-aligned focusing scale for visual reference during lens validation and focus testing. Supplied with a snug-fitting fabric storage case to maintain surface integrity. The 18% gray surface is used to derive accurate exposure values by metering off its uniform reflectance — forming the basis for consistent exposure across varying scenes and lighting intensities. The white side provides a known neutral reference for custom white balance — correcting for colour bias introduced by ambient light sources such as LED panels, tungsten bulbs or overcast daylight. Designed exclusively as a two-tone (gray/white) tool — no black surface is included or implied in manufacturing or functional design. Used by editorial photographers, commercial studios and educators to teach foundational exposure and colour theory — bridging the gap between theoretical knowledge and hands-on application in real-world shooting conditions.