Abstract Prismatic lead white was first described by Walter C. McCrone in 1983 when it was identified via polarised light microscopy in three paintings by Edouard Manet. It is characterised by crystals in the shape of bullets or pills (i.e. prism-shaped, hence ‘prismatic lead white’). McCrone attributed the formation of these crystals, morphologically distinct from those of ‘normal’ lead white, to processing conditions characteristic of precipitated lead white. These ‘prismatic’ crystals have subsequently been identified as cerussite (orthorhombic lead carbonate, PbCO3). Their presence has been tentatively used to date artworks painted from the nineteenth century onwards. The article will show, through reproducing historic pigment recipes of post-treatments, that prismatic lead white can also be formed in the stack lead white process and so its presence should not be used as a criterion for dating. This article investigates the formation of these prismatic crystals in the context of the manufacture and history of lead white.

中文翻译：

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棱柱形铅白的性质和意义的技术检验

摘要1983年，沃尔特·麦克罗纳（Walter C. McCrone）首次描述了棱柱形铅白，当时它是通过偏振光显微镜在爱德华·马奈（Edouard Manet）的三幅画中被鉴定出来的。它的特征是子弹或药丸状的晶体（即棱柱形，因此是“棱柱形铅白”）。McCrone将这些晶体的形成（在形态上与“普通”铅白的形态不同）归因于沉淀的铅白的加工条件。这些“棱柱”晶体随后被鉴定为陶粒（斜方碳酸铅，PbCO3）。他们的存在被暂时用来约会从19世纪开始的绘画作品。文章将通过再现后处理的历史性颜料配方来展示，棱柱状铅白也可以在叠层铅白工艺中形成，因此不应将其存在用作定年标准。本文在铅白的制造和历史背景下研究了这些棱柱形晶体的形成。