Mastic and Megilp in Reynolds’s 'Lord Heathfield of Gibraltar'

Rachel Morrison
Technical Bulletin Volume 31, 2010


Sir Joshua Reynolds’s portrait of Lord Heathfield (NG 111) was commissioned to commemorate the sitter’s defence of Gibraltar and his triumphant defeat of the Spanish siege. It was painted in 1787 towards the end of the artist’s career, by which time Reynolds had achieved wealth, success and a considerable degree of celebrity.

However, the painting began to deteriorate early in its life and it now suffers from the severe cracking and pronounced drying defects typical of so many of Reynolds’s works. The portrait was recently examined in the conservation studio and the results of the analytical and technical study are reported in this article, set in the context of the documentary sources relating to Reynolds’s painting techniques.

The use of a resin-containing binding medium such as megilp is discussed as a possible cause of the drying cracks and Reynolds’s use of varnish-like glaze layers is investigated. An improved understanding of the methods employed by Reynolds to create the portrait informed the assessment of the painting’s condition and appearance and was critical for evaluating suitable conservation treatment.


Sir Joshua Reynolds (1723–1792), Lord Heathfield, painting techniques, paint-binding medium, megilp, glaze, varnish, mastic, organic analysis, GC–MS, lead-tin-antimony yellow

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Mastic and Megilp in Reynolds’s 'Lord Heathfield of Gibraltar', Rachel Morrison (PDF 11.5MB)


To cite this article we suggest using

Morrison, R., 2010. 'Mastic and Megilp in Reynolds’s "Lord Heathfield of Gibraltar"'. National Gallery Technical Bulletin Vol 31, pp 112–128.

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  • Technical Bulletin Volume 32
    In this volume: Leonardo in Verrocchio's workshop – 'The Virgin of the Rocks' – painting practice in Milan in the 1490s – an altarpiece once in San Francesco Grande, Milan
  • Technical Bulletin Volume 33
    In this volume: Renoir’s 'Umbrellas' – Gerini’s 'Baptism Altarpiece' – Vuillard’s 'La Terrasse at Vasouy' - Adolphe Monticelli - 15th and 16th century European paintings
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    In this volume: Verrocchio – Giorgione's 'Il Tramonto' – 'The Virgin and Child with an Angel', after Francia – Perugino’s 'Baptism of Christ' – Rembrandt – Reynolds