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This article reviews the research recently undertaken to characterise and identify early synthetic dyes (ESDs) and synthetic organic pigments (SOPs) as well as study their degradation pathways with a focus on cultural heritage applications. Since the invention of the first fully synthetic dye in 1856, these materials have been used in a variety of historic objects and artworks, such as textiles, furniture, prints, paintings, drawings, etc. The synthesis of new dyes and their implementation into pigment formulations were rapid phenomena, so that by the beginning of the 20th century, thousands of new molecules were patented and commercialised. This review will focus on these early formulations synthesised up to approximately 1914 and the outbreak of World War I. ESDs and SOPs represent a challenge from an analytical point of view. Molecular databases are fundamental for the unequivocal identification of these compounds, but reference materials are not always readily available. A combination of analytical techniques is often needed for characterisation, especially in the case of SOPs, which have both organic and inorganic components. Furthermore, the degradation of these molecules can jeopardise their detection in historic objects that have been exposed to light, humidity and temperature fluctuations. Nevertheless, ESDs and SOPs are important research tools. As the dates of their first synthesis are often known with precision, based on patent information, their detection can be used to refine the production date of objects. Additionally, their trade from Europe to the world and their adoption in artistic practices around the globe is an active area of research. [ABSTRACT FROM AUTHOR]

Several microinvasive methods were applied to analyse the fibre materials from the Snartemo V burial from the Migration Period (fifth century CE) in Norway. The morphological parameters of the textile fibres and furs were examined with optical (TLM) and electron microscopy (SEM, SEM-EDX and TEM) and dyes with UHPLC-PDA method. According to TLM and TEM analyses, the Snartemo textiles were spun of very fine wool, that consisted of white and naturally pigmented fibres. The dye analysis revealed colourants referring to dyer’s madder, weld and woad in several textiles. The reddish hue in the warp of the wide geometrically patterned tablet-woven band was interpreted a result of the fading of the natural dark pigmentation of the wool. Respectively, the warp yarns that now appear yellow were interpreted as originally white, undyed wool. In addition, fibres from a bear’s (Ursus arctos) fur and a Mustelidae sp. were identified in the previously unexamined Snartemo materials. [ABSTRACT FROM AUTHOR]

The history, analysis, and use of the semi-synthetic dye indigo carmine is described by means of a study of historical sources including patents, dye identification using high performance liquid chromatography (HPLC), and the examination of dyed textiles. Indigo carmine, the acid dye 'Saxon Blue', was invented by Johann Christian Barth in 1743. Indigo carmine is a water-soluble blue acid dye with the advantage of an easy dyeing process. Its disadvantages are poor lightfastness and washfastness. For the identification of indigo carmine by HPLC, a gradient using water, methanol, and 0.5 mM tertiary butyl ammonium hydroxide can be used to give an unambiguous analytical result. Analyses of dated textile objects prove that indigo carmine was in use after 1770 until the beginning of the twentieth century. This study provides practising conservators with chemical, technological, and historical information which can help in the identification of textiles dyed with indigo carmine, and suggests ways of responding to poor washfastness. [ABSTRACT FROM AUTHOR]

Several case studies are described, all focussing on the analysis of archaeological objects. Research was done on objects from different materials, such as glass, textile and ceramics, from different pre-historical contexts and addressing different questions. In all cases, however, the analytical procedure was complex due to the nature of the archaeological material. We discuss the possibilities and limitations of different non-destructive and micro-destructives techniques. [ABSTRACT FROM AUTHOR]