ARCHITECTURAL WINDOWS and MECHANICS of VISION
Post 248 ⇒ by Gautam Shah →
Architectural windows have many sizes, shapes, form and locations. Wherever and for whatever intentions a window is placed, its most fascinating function is view out, and for some cases the view in. Wherever there is a little crack or opening in a wall like structure, one wants to discover the realm on the other side. Windows, enlarged or small in size, transgressed out and inward, pushed to the floor or roof, to regulate the scope of vision.
The mechanics of vision depend on several factors, such as: distances of the window frame, vision cone and the frame extent, sill level, lintel level, shading devices, size of window sides, window design or configuration, quality of glazing, level of maintenance, the differences of outside and inside illumination, amount of the glare, treatments on internal and external faces, quality of external surroundings, tasks, orientation, climatic conditions, lighting conditions, need for protection and privacy, etc.
The notion of the ‘eyes as the window to the psyche’ goes back at least to a text by philosopher Sextus Empiricus (2nd C AD).
The factors regulating the vision continue to evolve with new forms of openings, shutter systems and glazing technologies. A window is a frame, marking the edges of the aperture, and also the reference plane for the visual experience. The frame of a window reflects its structural dependence, but also aspirations for the structural un-susceptibility. The frame is not the body of a window, but rather the sized sides of the openings. The openings’ sides, sill tops and lintel or arched bottoms, in heavier wall structures imposed their presence, with the differential colour tone of the reflected light. These were, both, enhanced or dissolved with techniques like chamfering of sides, placing the window on an extreme inner or outer edge, texturing the side with flutes and carvings. The treatments to the sides affected the framing clarity of the vision.
The sides of the openings were encroached or enhanced by additional architectonic elements, such Jambs, sides, entablatures, architraves, pilasters, half columns, pediments, etc. These elements were intended to mould the appearance of the openings, but in many instances undulated the edges of the visual framing.
Glass windows have been prominent in domestic buildings since the 15th C, before, that these were employed in Gothic churches and public buildings. The Gothic windows were meant for the colourful effect, and due to a high plinth (sills were usually beyond the head level on ground floors) less for vision purposes. Compared to it, the Indian temples have remained without glazing, offer very little for vision-in, though vision out was through an axially placed opening.
Sections of the windows cause stratification of the view. Windows show views in three references: The higher view (above the horizontal eye level or head level), the middle view (within the nominal cone of vision) and the lower view (eye and the head both bend downward). The stratification of view becomes obvious when working some distance away (typically equal to one human height measure) from the window. A person working close to the face of a window may get all three views from a mid level opening. The strata are more pronounced in windows with horizontal baffles as the shading component.
Higher view from the upper section of a multi-story building shows up only sky, a very static view. But higher view in a low rise building shows upper parts of surrounding buildings, mid portions of trees, and horizon, a slightly changing view, but not strong enough to cause any distraction. Mid level views on busy streets, are distracting due to continuously moving objects outside, and varying illumination and reflections in the interior space. Mid level views from any floor are ergonomically not exerting for most tasks. Low level view from upper floors show up the grounds, gardens, lower terraces, water bodies, etc. All of these surfaces very strongly reflect the changes in solar illumination, shadows, moving objects, etc. The ceiling surfaces become extremely vivid due to the upward reflections, not an ideal proposition for bed rooms, rest rooms and hospital wards.
A fully stretched floor to ceiling window shows all the three views concurrently, and as a result there is no stratification of the view. The strata can be supported or diffused, by including or avoiding the horizontal elements in window design.
Open Zarokhas, bay windows and Latticed balconies, like at the Jaipur Hawa Mahal or Mashrabiya of middle east, are two opposite versions of street side openings.
Historically, windows have not been used for viewing in the interior spaces. Though small aperture openings, alone or as part of the doors, were used for eavesdropping, spying or casual observation (Darshan). These were small sized because the eye was placed very close to the aperture. Display cabinets and Aquariums have glazed fronts to display the items. Office and cabin doors have view windows.
Commercial spaces require people to see the interiors’ spaces and the goods and activities therein. Shop fronts are large format fixed glass windows. A shop front design depends on the angle of observation, difference between outside-inside illumination, angles of a light source, its size and intensity. Shop fronts are designed for clear and glare free view, achieved by treatments over glass, external shading devices and through back up illumination. The quality of glass and its cleanliness become very important issue. A view-in window like the shop front ensures security as a person breaking-in is likely to be observed.
The cone of vision is determined by the width of the window and depth of the room. A corner side window cuts off the view compared to a centrally positioned window. Ribbon like horizontal windows are called panoramic openings, whereas spot windows are called picture openings.
Panoramic views became popular with curtain wall structures. Here the horizontal members are placed floor level, and verticals are widely spaced or concealed. The glass walled window has the R-value of 3, which is the same as an inch of corrugated cardboard, making it a space of uneven temperatures. A study by the Urban Green Council, says that 59% of New Yorkers keep the blinds closed over their big glass windows.
The excitement of the frontal panoramic view and domed eye view of Pantheon have gone a step further. It started with Caboose rail wagons, where a dome projection over the roof allowed all round vision. The view down is being tried in many different formats. Sears Tower in Chicago has installed four glass box viewing platforms or sky-deck (called Deck) that juts out 1.2 mt, at 103 floors level.
The television screen as a replacement of a traditional window, creates ‘spatial ambiguity between public and private space’. In German post-war-architecture, the transparency of glass was equated with the transparency of the democratic government (dome of the former Reichstag in Berlin).