The influence of background color on colorimetric accuracy in dental photography: a multi-specimen spectrophotometric analysis

Objective. To evaluate the influence of background color on shade accuracy in dental photography. Methods. Forty-eight specimens were photographed against neutral gray, black, blue, and pink backgrounds using a locked white balance setting. Reference color values were obtained with a validated spectrophotometer. Color differences (ΔE₀₀) were analyzed using linear mixed-effects models and clinical threshold analysis. Results. Background chroma significantly affected colorimetric accuracy. Neutral gray backgrounds produced the lowest color errors, with 58-71% of specimens below the perceptibility threshold (CIEDE2000 ΔE₀₀ = 0.8). Saturated backgrounds produced large color errors, with 92–100% of specimens exceeding the acceptability threshold (CIEDE2000 ΔE₀₀ = 1.8). Directional coordinate analysis supported the role of inter-reflection as the underlying mechanism. Conclusions. Colored backgrounds may introduce clinically unacceptable color errors through inter-reflection, which cannot be corrected by white balance alone. Neutral gray backgrounds are therefore recommended for shade-critical dental photography.