The group of prints were significantly distorted, with concave and convex waves of planar distortions across the top edge, middle right, and middle left edges in response to the hinges that hold the work to its back mat. The prints were humidified and flattened using moisture followed by drying under weight. The use of corners was recommended instead of hinging due to the extremely moisture-sensitive paper support.

Image credit:
Amon Carter Museum of American Art, Fort Worth, Texas, Purchase with funds provided by the Cynthia Brants Trust

The watercolour was stained and discoloured. Surface grime marred the support and was embedded in the impasto areas of the media. Severe vertical planar distortions were present along the upper half of the watercolour. Small brown spots stained the artwork and were especially pronounced in the upper half of the sheet. Surface abrasion was present at the lower left quardrant of the artwork. The watercolour was adhered to a secondary support at four points with animal glue. Once the secondary support was mechanically removed, the verso of the artwork could be examined. The verso was discoloured overall  with stains at all four corners from oxidised animal glue residue. The oxidised adhesive residue was reduced using a poultice of methyl cellulose paste. The watercolour was humidified under pressure, and washed via partial immersion in calcium hydroxide. Soluble degradation products and discolouration were reduced, and insoluble acids in the support neutralised.

Condition report and technical examination
Treatment proposal
Treatment report

Before treatment – Normal light – Recto

After treatment – Normal light – Recto

Before treatment – Raking light – Recto

After treatment – Raking light – Recto

The hand-coloured lithograph was severely discoloured where it was not covered by a mount or frame. Surface grime marred the print; additional brown accretions were present along the margins. Multiple tears, losses and pin-hole sized punctures were also present along the edges of the print. The print was surface cleaned using grated eraser shavings. It was humidified and washed to neutralise the acids in the paper, and remove soluble degradation products. Tears and losses were pulp filled, improving both the aesthetic and structural stability of the print. To protect the print during storage, a clamshell folder was made to the specifications of the print.

Condition report and technical examination
Treatment proposal
Treatment report

Before treatment – Normal Light – Recto

Before treatment – Raking Light – Recto

Before treatment – Normal Light – Verso

During treatment – washing the print using the low-pressure table

During treatment – creating pulp samples to achieve a close pulp match

During treatment – applying toned pulp with a dropper to fill losses

After treatment – Normal Light – Recto

After treatment – Raking Light – Recto

After treatment – Normal Light – Verso

Abstract:

Not much research has been done in the field of British hand-coloured prints in the 18th and 19th centuries. This paper provides a brief overview of the history and production of hand-coloured prints, the people involved, and the common materials used. Three sensitive yellow pigments gamboge, quercitron and chrome yellow, which were commonly used in hand-colouring are also discussed in detail, covering their history, physical and chemical properties, as well as methods of identification. These pigments were selected due to the common usage of yellow pigments in many hand-coloured prints, used both alone and as a mixture to achieve numerous shades of green and orange. Yellow pigments are also known to be very fugitive pigments, with these three pigments being some of the most sensitive. The details of their sensitivities are then used to provide possible aqueous treatment options for the conservation of hand-coloured prints, with focus on the removal of discolouration and soluble degradation products. Possible treatment options include double-screen washing, blotter washing, low-pressure table washing, partial immersion, and the use of rigid Gellan gels. Local and targeted treatment options as well as additional treatment steps like fixing and the use of templates are also discussed.

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