Colours play a crucial role in the field of architectural heritage. Colour analysis and colour rendition are involved in several critical facets of heritage preservation, conservation and restoration. These aspects are related to accurate documentation and an accurate representation of heritage artefacts and architectural works. The aim of this paper is to describe critical issues and open problems of the processes involved in this field. Documentation is performed in multiple ways, acquiring heterogeneous data ranging from archival images, photographs, drawings using various consumer or professional instruments (eg, digital cameras and spectrophotometers). The reliability of colour acquisition might be influenced by instrumental reasons (the technology used to acquire colour information), by environmental changes (architectural heritage surveys are often performed outdoors), by morphology (complex architectural objects are characterised by concavities and convexities which complicate the reflection evaluation), or by materials (showing different reflection, porosity and transparency indexes). Identification of materials, such as colorants, pigments and dyes, is also a vital process in the heritage field. Colour information could be used as an approach to the identification of materials, but these methods are still under development, and many issues need to be solved to achieve reliable results. Visualisation techniques of a heritage artefact also present the problem of the correctness of the colour representation. Several problems need to be faced in this context: the reliability of the acquisition, colour management of the rendering software, model complexity, and fragmentation of the devices upon which the model is visualised.

中文翻译：

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文化和建筑遗产的保护和恢复：哪种颜色？

颜色在建筑遗产领域中起着至关重要的作用。颜色分析和颜色再现涉及遗产保护，保护和恢复的几个关键方面。这些方面与准确的文献记录以及对文物和建筑作品的准确表示有关。本文的目的是描述该领域所涉及的过程中的关键问题和未解决的问题。记录以多种方式执行，使用各种消费性或专业仪器（例如，数码相机和分光光度计）获取从档案图像，照片，绘图到各种数据。颜色获取的可靠性可能受到仪器原因（用于获取颜色信息的技术）的影响，通过环境变化（通常在户外进行建筑遗产调查），通过形态（在复杂的建筑物体上具有使反射评估变得复杂的凹凸）或通过材料（显示出不同的反射，孔隙度和透明度指标）来实现。鉴定材料，例如着色剂，颜料和染料，也是遗产领域的重要过程。颜色信息可以用作识别材料的方法，但是这些方法仍在开发中，需要解决许多问题才能获得可靠的结果。传统文物的可视化技术也提出了颜色表示正确性的问题。在这种情况下，需要面对几个问题：收购的可靠性，