väriarviointi

Väriarviointi is the process of assessing color properties of surfaces, products or images. It combines subjective sensory evaluation and objective instrumental measurement to determine whether colors meet specified criteria or tolerances. In practice, evaluators examine under standardized illumination, using trained panelists or reference samples, and record judgments about hue, chroma, and lightness.

Methods include both visual and instrumental approaches. Visual evaluation uses controlled lighting conditions (often standard daylight such as D65), neutral surroundings, and rating scales or color charts to compare samples with references. Instrumental colorimetry employs devices like spectrophotometers or colorimeters to measure spectral reflectance and convert data into color spaces such as CIE L*a*b* or LCh. Color differences are quantified with ΔE values, commonly ΔE*ab or ΔE00, where smaller numbers indicate closer color matches.

Applications span quality control in industries such as paints, textiles, plastics, coatings, food packaging, and cosmetics; branding and product design to maintain consistent appearance; printing and digital imaging workflows; and art conservation where faithful color reproduction is essential. Väriarviointi also addresses perceptual issues like metamerism, where colors match under one illumination but differ under another, making standardized lighting and viewing conditions crucial.

Considerations for robust evaluation include observer variation, sample texture, aging effects, and the geometry of measurement. Effective color management requires calibration, defined tolerances, and documented procedures. Standards referenced in practice originate from international colorimetry guidelines established by the CIE and ISO, as well as industry-specific measurement and reporting protocols.