Comparative Evaluation of Ageing Pathways for Silk Under Arid‐Region‐Relevant Conditions: Archaeometric Implications of Salt Cycling

This study established a comparative laboratory framework to evaluate ageing pathways for silk under conditions relevant to arid northwestern China. Uniformly degummed silk specimens were subjected to photo‐ageing, dry‐heat ageing, humid‐heat ageing, acid/alkali cycling and salt cycling, and the resulting changes were assessed by total colour difference (Δ E * ab ), maximum force and tensile strength. All pathways induced measurable visual and mechanical deterioration, although their effects differed markedly in severity and discriminative capacity. Among the tested pathways, salt cycling showed the strongest overall sensitivity, and the CaSO₄ system produced the most pronounced response, including substantial colour change and severe mechanical loss after relatively few cycles. By comparison, NaCl and Na 2 SO₄ induced weaker or less stable effects, photo‐ageing mainly enhanced visible alteration, and the other pathways remained comparatively mild within the adopted timescale. These results indicate that salt cycling, particularly in calcium‐containing systems, provides a sensitive and discriminative laboratory route for assessing deterioration behaviour of silk under arid‐region‐relevant conditions. The study provides a practical and archaeometrically relevant basis for selecting laboratory proxies of silk deterioration, as well as for designing artificial ageing protocols and evaluating conservation strategies for silk heritage materials.