A Handful of Weld Yellows - Unravelling 18th Century Recipes From French Master Dyers Antoine Janot And Paul Gout

• Autor(a) principal: Santo, Mara Catarina Duarte do Espírito
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/162740
• topic: Yellows; Weld; Antoine Janor; Paul Gout; Molecular fluorescence; HPLC-DAD; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

In textile production, since the pre-historical times until mid-19th century the main source used for dyeing were natural colorants from plants and animals. Using natural colorants as a source of color implies a deep understanding of chemistry, which the dye masters of the French manufactures from the 18th century were already familiar with. From an extensive color pallet, yellow distinguishes itself, by its brightness, but also be-cause it is used to produce other colors, like oranges, greens, light browns, some reds and even some blues. But with the advent of the synthetic dyes, in mid-19th century, the organic color-ants were forgotten, so much so that the organic yellows gained a bad reputation, linked to its sensibility to light, and started being referred to as "lost yellows". However, studies have shown that the stability of a certain colorant is directly linked to the formulations of the recipe. The main goal for the present thesis is to contribute to the research on the dye formulations, by exploring the recipes of two French master colorists: Antoine Janot and Paul Gout. This step has already been of the upmost importance in the deciphering of these yellows, from understanding the use of weld; but also, how the ingredients of the recipes, with different concentrations, have a major influence. Molecular fluorescence proved, once again, to be a key element in deciphering these recipes, and in the organic colorants. HPLC-DAD confirmed our data, proving the influence of tartar and lime in these reconstructions, where it can be seen the importance of the pH. The next step would be to continue to explore molecular fluorescence, comparing the data obtained from the reconstruction to the micro samples collected from the memoirs of the master dyers. It would be interesting to explore the influence tartaric acid has when complexing the chromophores to the wool, as well as explore different subtracts with this same capacity, a work that has already taken its firsts steps.