amarilleo

Amarilleo is a Spanish term that describes the yellowing of materials as a result of aging and environmental exposure. In conservation science and materials studies, amarilleo is commonly observed in paper, photographs, textiles, wood, and varnishes, and it is often used to assess the aging state of objects.

Causes and mechanisms: The most frequent cause is oxidation of lignin in wood-based papers, which forms chromophores that impart yellow to brown tones. Photo-oxidation from ultraviolet and visible light also contributes, as do acids and pollutants that accelerate chemical changes in fibers and coatings. Over time, these reactions alter the color and may also affect mechanical properties, such as embrittlement in paper and textiles.

Materials affected: Paper (especially high-lignin or acidic substrates), photographs and film emulsions, textiles containing cellulose or proteins, varnishes and oil-based paints, and wooden objects or furniture. The specific pattern of amarilleo varies with fiber composition, coatings, and exposure history.

Impact and measurement: Amarilleo can reduce readability, alter appearance, and indicate the degree of degradation. Conservators quantify color changes using colorimetric methods and spectroscopy, tracking shifts in parameters such as lightness and color coordinates to monitor progress and guide treatments.

Prevention and treatment: Preventive measures include controlling temperature, humidity, and light exposure; using UV-filtered lighting and inert storage environments; and employing acid-free storage materials. For some items, deacidification or stabilizing treatments can slow progression, but reversal of yellowing is often limited and bleaching or invasive procedures must be carefully weighed against potential damage to the substrate.

Etymology and usage: In Spanish-language literature on aging and conservation, amarilleo is the standard term for yellowing disorders, used across disciplines from archivistics to art conservation.