The technique of mural painting. Taking down, transferring and arrival in the museum

The most important part of the collection of mural painting of the museum was gathered together in an operation carried out between 1919 and 1923.  It had been discovered that the Romanesque paintings of the church of Santa Maria de Mur, in the Pallars Jussà, had been sold and removed from the wall.  It was therefore considered that the rest of the Catalan Romanesque mural painting was at risk.  The decisive action of the Board of Museums and Joaquim Folch i Torres, the director of the museum at that time, turned the situation round.  Between the autumn of 1919 and 1923, the paintings were acquired, they were removed from their original support, the walls of the churches, and they were transferred to Barcelona, where they were fixed to another support and made ready to be exhibited in the museum.  

Nearly all the Romanesque mural paintings of the museum were removed from the walls using the Strappo technique, that is to say, only the pictorial layer is extracted, leaving the plaster coating on the original wall. 

In the technical process of painting on a wall in the open air, the pigments are applied on the wall on a layer of mortar that is still damp.  When the mortar dries, the pigments crystallise along with the mortar itself.   

In Catalonia, the pigments most used in the Romanesque period were natural earths from the Pyrenees: haematites for red or aerinite for blue.  In exceptional cases imported ones were used, such as lapis lazuli or azurite for blue.