Transparency and immateriality have been obsessive aspirations in modern architecture following the prediction of Karl Marx, “All that is solid, melts into air”. However, this obsession with unobstructed visibility has weakened the sense of gravity and materiality, secrecy and shadow, as well as the primary difference between inside and outside. Material surfaces have turned into reflections and the immaterial imagery of dreams and the unconscious. Glass and transparency were intended to enrich and dramatize architectural expression, but they have eventually resulted in uniformity, repetitiousness and boredom.

This trend has gradually given rise to ideas and works that aim to restore the lost sense of mystery, layeredness and depth. Architectural history provides splendid examples of variously penetrable surfaces, from Gothic stained-glass windows to Islamic and Indian carved stone walls that filter light and visibility. Also, modern architects have developed surfaces and devices that articulate and mediate visibility and textural experiences, such as the porous “textile blocks” of Frank Lloyd Wright, the sun-breakers of Le Corbusier, and the wood lattices and surface textures of Alvar Aalto. The means of creating layered and tactile visual experiences have multiplied with today’s new ideas and materials of translucency, as exemplified by the printed ornamentation of Herzog and de Meuron, Steven Holl’s ideas of “porosity”, and Kengo Kuma’s examples of “dematerialization” or “particlization”. Finally, today’s material technologies are producing materials that adjust their degree of transparency and solidity, as well as other properties in accordance with the changing conditions of the environment. Surfaces simulate the dynamism of living skin.

These devices give a sense of depth, mystery, surprise and temporal duration to vision. We know how laces and veils can eroticize the human body by hiding and creating ambiguity; veils and curtains evoke our curiosity and imagination. Even light is invisible until it strikes a surface or penetrates into a material. James Turrell, the alchemist of light, speaks of the tactility and “thingness” of light. Light becomes especially emotive when it is caught by a mediating substance, such as water, rain, mist, smoke, or a translucent material, such as marble or alabaster. Light turns into a radiant and colored air or liquid. Great painters, from J.M.W. Turner to Claude Monet and Mark Rothko, have also transformed light into embracing colored substances.

As a consequence of the constant acceleration of the speed of life, time is also disappearing from human experience. This simultaneity is exemplified by the reflective surfaces of corporate architecture. When time and duration are caught and held through processes of erosion, decay and wear, they metamorphose into sensuous, tactile and comforting experiences. Ruins have a particular appeal as they tame human arrogance, halt duration and invite our touch. Like light, time can also turn tactile through architecture and art, as in the great novel of Marcel Proust, In Search of Lost Time.