Cleaning and Consolidation

Aspects of cleaning, as well as consolidation, have already been discussed when dealing with the barium method of extraction and consolidation. So in this section, cleaning in the context of salt extraction will not be referred to anymore. However, there are other materials that become part of the paintings over centuries of intensive use, as well as previous conservation treatments. Many of these materials were applied as a consolidation treatment. This section will therefore consider different consolidation methods before discussing how to reduce their sometimes detrimental effects. 

During consolidation of plaster and rendering, problems arising may be the same as that of surface consolidation. However, to see these changes beneath the paint layer in the early stages may be much more difficult. Modem 

Consolidation generally can be divided into two types of methods inorganic or organic consolidants. The latter may be natural organic polymers or even synthetic polymers. Both types of treatment may cause longer-term drastic alterations although acceptable results may have been obtained directly after application. 

Consolidation by inorganic materials. Up to now, a mineral treatment such as the application of barium hydroxide (described earlier) seems to be the only method that does not turn out to be detrimental in the end, as long as it is applied carefully and under the right conditions. 

Consolidation by organic materials. More commonly, organic polymers have been applied for consolidation of paint layers. Natural polymers were most frequently applied in Europe, including animal glue, casein, egg yolk 

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Occasionally, determination of properties of the aqueous solution in equilibrium with the solid, such as pH, conductivity, or concentration of ionic species is also of interest—in particular, in the monitoring of cleaning and consolidation of archaeological artifacts. 

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