The full chromatic range of the painting was obscured by a very discoloured yellow varnish layer, muting the artist's intended variation of tone and colour. All varnish layers deteriorate with age in this way, and it is a common task of painting conservations to carefully remove aged varnish layers from oil paintings and replace them. The varnishes used today have better ageing characteristics and are not expected to deteriorate as quickly and as dramatically as older types. Maintaining the painting within a gallery environment with filters that remove the damaging ultraviolet component of light also assists in reducing the deterioration of varnish layers.

Removal of varnish from right

The varnish on the painting is not the original varnish. The painting has already undergone several restoration treatments since its completion by the artist. The current varnish is Mastic; a resin extracted from a small tree, Pistacia Lentiscus, most commonly found on the Greek island of Chios.

As the chemistry of oil paint and resins are quite different it is possible with careful testing to find a solvent system for the varnish which does not affect the paint layer. This solvent is applied on small cottonwool swabs to the surface of the painting in order to carefully remove the varnish.