A monopteros temple, sheet X/4
The conservator will make a staining assessment of a drawing in order to
- analyse the type of stain
- select treatment and test suitability
- treat the stain overall or locally
Stains caused by water and adhesives are usually easily removed; oil, varnish or waxes are more difficult to break down, as are pressure-sensitive tapes.
Ink or other drawing material stains are not considered for removal due to their historical importance as they are considered to be part of the drawing creation process.
Water stains and tide lines will fluoresce under UV.
Water or organic solvents can be applied to remove a stain, although repeated use of solvents will eventually desiccate the paper. Supports with less sizing will make the stains more difficult to remove as the paper will be weaker and less tolerant as the stains will penetrate deeper into the paper's substrate.
The stain will have to respond to the solvent; not all solvents will work on all types of stain. The evaporation of the solvent will affect its efficiency in removing the stain. Modifications can be used to ensure a greater efficiency through concentration or mixture of solution, or by its application to the sheet itself.
Treating sheet X/4
Excess animal glue at the edges of sheet X/4, as seen in the image under magnification, was reduced locally using a solution of warm water through a suction point. The treatment reduced the discolouration to the paper minimally, removing soluble areas of the stain. The suction point is a useful tool in removing staining when the drawing material is sensitive or the paper is fragile in areas.
The staining along the right-hand side was not removed as this type of stain would require extensive treatment.
The drawing was inlaid and mounted prior to framing.