conservation image Wall Paintings at Mogao Grottoes
 

Environmental data shows a correlation between a loss of painted plaster in Cave 85 with rainfall and corresponding increases in exterior and interior relative humidity (RH) values. RH values inside the cave reached to over 75% the RH equilibrium for NaCl. Given the high values of NaCl found in the plaster, the change in RH most likely contributed to the loss of the wall painting. Credit: Getty Conservation Institute.