Britain’s Lost Masterpieces (BBC4) – A portrait from Sir Joshua Reynolds

In May 2021, Factum Foundation were contacted by Tern TV, producers of Britain’s Lost Masterpieces, and asked whether it might be possible to digitally restore a portrait by Sir Joshua Reynolds, possibly of Elizabeth Linley, held in the collections of the Glasgow Museums and at that time in the temporary keeping of the conservator Simon Gillespie.

The portrait, which formed the key object for an episode of the program presented by Emma Dabiri and Bendor Grosvenor, had proved impossible to restore using ordinary conservation techniques due to the presence of ingrained varnish, which had given the whole work a strong yellow cast. Factum Foundation was able to record the painting and digitally restore the colour profile as closely as possible to the colour of the original painting. The sitter was also later identified as Lady Anne, Duchess of Cumberland.

Over the course of the project, it was decided to reproduce the restored data as a physical facsimile, which was donated to the Glasgow Museums and is now part of their collection.

Recording the painting

The painting was recorded in high resolution inside Simon Gillespie’s conservation studio using the Lucida 3D Scanner: a non-contact laser scanner, developed by artist-engineer Manuel Franquelo with Factum Arte, which was able to acquire the subtle surface relief. Once processed as a shaded render, it proves to be an important additional layer of information regarding the state of conservation of the painting, and it is one of the requirements to make an accurate facsimile.

The colour was recorded using composite photography, supported by an X-rite colour checker to ensure an accurate result.

The Lucida 3D Scanner recording the surface of the painting inside Simon Gillespie’s studio © Elizabeth Mitchell for Factum Foundation

Elizabeth Mitchell describing the Lucida 3D Scanner at work to conservator Simon Gillespie © Factum Foundation

Detail of the Lucida 3D Scanner recording the surface of the painting © Factum Foundation

Celestia Anstruther operating the Lucida 3D Scanner on painting © Elizabeth Mitchell for Factum Foundation

Colour processing and digital restoration

Over the summer of 2021, the 2D team at Factum Foundation worked on the digital restoration process. In order to do this, Factum’s colour specialist Gabriel Scarpa first compared the recorded data for the portrait with the colour data of Reynolds’ Ladies Waldegrave, currently in the National Galleries of Scotland in Edinburgh. The painting was recorded by Factum Foundation in 2018 in order to create a facsimile for Strawberry Hill House, its original location, and provided a precious reference – though, as it was pointed out by conservators, not knowing the precise conservation history of the Ladies Waldegrave should be taken into account when assessing the accuracy of the restored facsimile.

The first stage of restoration was to create tests that removed the yellow cast of the Glasgow portrait. The baseline colours to be followed were determined by the colour palette of the Ladies Waldegrave. After consulting with Simon Gillespie and Reynolds experts, it was decided to also digitally remove some varnish spots around the face and neck of the portrait.

Teresa Casado working on the digital restoration using The Ladies Waldegrave as reference for colour © Oscar Parasiego for Factum Foundation

Teresa Casado working on the digital restoration using The Ladies Waldegrave as reference for colour © Oscar Parasiego for Factum Foundation

Composite image showing the various initial tests © Factum Foundation

Detail of the original painting © Factum Foundation

Digital restoration before removing the pooled spots of varnish © Factum Foundation

Making the facsimile

The digital data for the surface relief was rematerialised as a physical object using the elevated printing technology developed by Canon Production Printing (CPP), with whom Factum has collaborated over many years. The revolutionary elevated printing method is capable of building up a relief surface in 5-micron layers in order to replicate the exact surface of a painting.

Liquid silicone was poured over the monochrome (white) relief print to create a mould of its surface. A cast was then made from this mould using a specially prepared acrylic gesso mix. This ‘skin’ forms the surface of the final facsimile, over which the colour was printed using Factum’s purpose-built inkjet colour printer.

Using a traditional method of registration, the colour and the relief are perfectly aligned, ensuring that the appearance of each facsimile is entirely faithful to the original. Multiple layers of over-printing ensure that the tone and hue of each colour correspond precisely to the colour of the original. The finished printed skin was then backed on board.