The bleeding phenomenon, a persistent and widespread issue in the application of cobalt-bearing pigment during porcelain decoration, has spurred different civilisations to develop various response strategies to alleviate this problem. In this study, we challenge the prevailing hypotheses concerning the role of composition and viscosity in determining the bleeding effect on blue-and-white wares, proposing a novel physical model framing it as a diffusion process that occurs within vitreous silicate, where the severity can be qualitatively expressed using the diffusion distance. Drawing upon the phenomenological Fick's law and microscopic diffusion mechanism, we quantitatively discuss the primary physical parameters that influence the diffusion behaviour for the first time, clarifying that the diffusion of cobalt ions is not related to the medium viscosity. Moreover, compared with the microstructural features of blue decors with and without the bleeding effect, we reveal that domestic cobalt particles are all encapsulated by anorthite crystals, acting as a passivation shell to hinder the dissolution of cobalt particles. Significantly, our reinterpretation has broader archaeological implications for the bleeding effect associated with cobalt pigment in ceramics, elucidating the historical trajectories of responsive practices and the multifaceted interplay between resource form, artistic expression and technological advancement across varying environmental and cultural contexts. Overall, these responses to the bleeding effect exemplify the complexities of technological evolution, highlighting that technology is not merely an extension of technical knowledge but also functions as a form of social construction deeply intertwined with its local context. This comprehensive understanding contributes to our understanding of historical narratives in ceramics and the diversity of human ingenuity in ancient societies, with potential implications for contemporary pigment manufacture.

中文翻译：

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回顾历史钴瓷颜料的渗色效应：机理、影响和技术应对


渗色现象是瓷器装饰中含钴颜料应用中长期存在且普遍存在的问题，促使不同文明制定各种应对策略来缓解这一问题。在这项研究中，我们挑战了关于成分和粘度在确定青花瓷器渗色效应中的作用的普遍假设，提出了一种新颖的物理模型，将其描述为发生在玻璃硅酸盐内的扩散过程，其严重程度可以使用扩散距离来定性地表达。借鉴唯象菲克定律和微观扩散机制，我们首次定量讨论了影响扩散行为的主要物理参数，阐明了钴离子的扩散与介质粘度无关。此外，通过对比有和没有渗色效应的蓝色花色的微观结构特征，我们发现国产钴颗粒均被钙长石晶体包裹，充当钝化壳，阻碍钴颗粒的溶解。值得注意的是，我们的重新解释对陶瓷中钴颜料的渗色效应具有更广泛的考古学意义，阐明了响应实践的历史轨迹以及不同环境和文化背景下资源形式、艺术表达和技术进步之间的多方面相互作用。总体而言，这些对出血效应的反应体现了技术进化的复杂性，强调技术不仅仅是技术知识的延伸，而且还是与当地环境深深交织在一起的一种社会建构形式。 这种全面的理解有助于我们理解陶瓷的历史叙述和古代社会人类聪明才智的多样性，对当代颜料制造具有潜在的影响。