The second principle the unity of opposites, contrast of the light and the dark, chromatic and achromatic is, the third principle is the adaptation of colour to the possibilities of human perception. Colour contracts and gloomy magnificence create the impresslon of greandeur that was characteristc to old Roma. It was the attempt of industrlal design. The restraint of colour of gloomy gray town colld the neccessity of light emotional effects. If the sky was under threatening over the Colliseum the golden silk was spreaded, that gave the illusion of sun light.
Romanic architecture concentrates the colour inside the building, the facade are monochromic.
The masonry was covered with thin layer of expensive stone materials or with time. Chromatic asceticism of monasterial complexes, castles and churches prevailing over town was emphasized by colourness of residential area. Gothic art canders the colour as natural attribute of architecture. The monumental cathedrals intended for future generations were made from stable materials and treated dy longelived colourbearers. The vast buildings dominant over town were made from gray and bronw limestones, sandstones of different tints.