The reason for her choice is <span>Ultraviolet rays will fade the paint pigment and high temperature and humidity will damage the paint.
the Frequency of the ultraviolet rays would break down the chemical bonds that construct the color of painting oil. Humidity would also cover the painting with moisture that would lead to discolorization. </span>
<span>A block placed at the summit of an arch or other structure, locking the whole together; a keystone.</span>
