Colourless Powdered Glass as a Drier for Red Lakes: On the Influence of Composition and Particle Size

ABSTRACT

Colourless glass particles are found in oil painting layers from the fifteenth-seventeenth centuries. Several historical sources mention the use of finely ground glass powder as a solid drier. In order to assess the siccative effect of glass particles added to paint, this research focused on red lake reconstructions and followed their natural drying using Fourier transform infrared (FTIR) analysis. Three glasses with different sodium-potassium and manganese contents were studied. Significant differences in drying rates were observed in each of the samples, indicating a relationship between both the composition – either enriched with or without manganese – and the size of the glass particles added as siccatives. This FTIR approach highlights several complex mechanisms involved in the drying effect of glass powders mixed in paint layers.

KEYWORDS:

• Powdered glass
• oil paint
• FTIR
• red lakes
• historic sources
• drier

Acknowledgements

The authors thank Isabelle Biron (C2RMF) for fruitful discussions and help about the nature and composition of the glasses. The authors also thank Lucy Cooper and Berfin Karakalic for the preparation of the glasses considered in the present research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Paris Seine Graduate School Humanities, Creation, Heritage, Investissement d'Avenir ANR-17-EURE-0021 – Foundation for Cultural Heritage Science – Fondation des Sciences du Patrimoine.