The varnish of times gone by
Lacquering is a finishing technique that consists in covering an object with a resinous substance – lacquer – in order to protect it or, in the majority of cases, to decorate it, creating a layer that is resistant to humidity and high temperatures and an effective barrier against woodworm and other insects. There are various lacquering techniques but the one practised in Europe since the seventeenth century is of Chinese origin.
The phases of the process
The base. The first phase of lacquering consists in covering the entire piece of furniture with a layer of glue so that the wood can absorb it, closing its pores; subsequently, various layers of gesso and glue are applied until achieving an even surface, which is smoothed with very fine sandpaper.
The decoration. In the next phase, a base colour is applied and the actual decoration begins, painting flowers, flourishes and geometrical figures in casein tempera with a brush and then possibly going on to the gilding phase.
Finishing. Once the decoration and gilding has been completed, various layers of sandarac varnish are applied. Sandarac is a rubbery addition to the varnish, which with its characteristic straw yellow colour, changes the shade of the lacquer. Depending on the layers of this varnish, a warm and transparent shade can be achieved: for example, a special yellow is obtained by painting sandarac on a white base, whereas the classic greenish shade is the result of one or more layers on a light blue base.