The architect Edward Durrell Stone built this Manhattan townhouse for himself at 13 East 64th Street in 1956. Stone's American Embassy in New Delhi was under construction at the time of its design. He had given the embassy a similar screen to protect it from the sun, and here recycled the idea for privacy. Stone would go on using screens to the point of being ridiculed for it. Nonetheless, his house introduced a new and subtle effect to New York, and it holds a key position in the history of windowflage. It looks back to Alexander Jackson Davis's 1835 American Institute project, with its upper floor windows camouflaged into a unified element, and forward to our own time's layering of building-scaled veils over windows.

Alternatives to the played out tinted-glass-box approach to windowflage have been explored with increasing frequency and variety since the 1990s. One design stream has superimposed façade-like screens over windows that are visible or expressed from below. The screens range from the uniform and static, like Edward Durrell Stone's mid-century forerunners, to screens with window-like voids or openable sections of their own.

A rail yard signal box by Herzog & de Meuron was included in the Museum of Modern Art's 1995 exhibition, "Light Construction." It is wrapped in copper bands that protect internal equipment from electrical interference. The bands are twisted in places, allowing natural light into the building's few windows and creating a layered facade that is at once a building with punched window openings and a sheer-sided object. The resulting depth and ambiguity make art of a utilitarian building. Located in Basel and completed in 1995, the building was exhibited alongside others with high-concept envelopes, including Jean Nouvel's 1994 Cartier Foundation for Contemporary Art and Fumihiko Maki's 1992 competition entry for a Congress Center in Salzburg which layered louvers and perforated metal over glass. The exhibition recognized an emerging exploration of the nature and potential of architectural surfaces. Herzog & de Meuron, who won the Pritzker Prize in 2001, have made this their territory as no one else, layering windows with everything from silkscreened leaves to boulder-filled gabions.

Media mogul Barry Diller was so taken with Frank Gehry's white model of his IAC headquarters that he asked for a white building. Gehry accommodated with a glass curtain wall that gradually varies from white to clear, at the level of each floor's sight-lines. Diller's initial impulse highlights the appeal of a building as a unitary sculptural object, while Gehry's compromise points up the inherent conflict between this desire and the need for windows. Architectural models have a special appeal that works on several levels. Robbed of useful size, the building in model form is almost purely sculptural. Reduced to an innocuous scale that the mind, or even the hand, easily grasps, it appeals to the part of the brain that takes pleasure in toys. One role of recent windowflage techniques is to visually shrink buildings which might otherwise intimidate with their size or complexity.

The IAC headquarters achieves its gradual transition from white to clear by way of a silkscreened pattern of ceramic paint on its glazing, or "fritted glass." Available in unlimited patterns and colors, fritted glass has become a ubiquitous plaything of architects who often justify it in practical terms as a way to reduce heat gain through partial shading. As with all screen-based windowflage techniques, however, it imposes a barrier at extra cost to the daylight and views which a glass building envelope provides at already higher construction and maintenance costs. Given advancements in glass technology that otherwise reduce heat gain, fritted glass is only justified on esthetic or privacy-related merits.

A rendering of Renzo Piano Building Workshop's New York Times Tower of 2000-07 emphasizes the consolidating effect of its screen. Piano has described his design as "simple and primary." Typical of windowflage from Alexander Jackson Davis's American Institute through the Edward Durrell Stone House, the multi-story unifying effect starts not at the ground, but rises from the top of the first floor. The special street-relationship of the first floor is thus enhanced, and a conflict between doors and a sheer screen avoided.

Countless exquisite brackets suspend the Times Tower's screen, as shown in this construction photo. Piano has been working outside the box with such elegant castings since his career-making Pompidou Center of 1971-77.

The Times Tower's ceramic tube screen casts acres of film noir cliché shadows inside, as shown in this construction photo. "The screen wall both deflects solar gain and heightens atmospheric effect," according to its description in the 2004 Museum of Modern Art "Tall Buildings" exhibition. It also affects views in ways that may not always be appreciated by occupants.

The Times Tower's screen is a skyscraper-height array of tens of thousands of cylindrical white tubes. They begin at the top of the first floor and extend up well beyond the roof, obscuring rooftop equipment and allowing the tower to dissolve into the sky. Piano began exploring the use of such external "venetian blinds" in his 1986-96 mixed-use Cité Internationale in Lyons, France and used them extensively on the Debis (Daimler Financial) Headquarters in his huge 1992-99 Potsdamer Platz project in Berlin. Instead of white rods, Piano's earlier projects used aluminum slats, rectangular in section and painted reddish brown to match adjacent terra cotta façade panels.

Edward Durrell Stone's residential screen is updated by way of the Times Tower in an extensive row house renovation now nearing completion at 252 West 75th Street. Designed by workshop/apd, the project's debt to Piano's Tower is clear in details like the wider spacing of the screen's bars at window bottoms and the exposure of the glazed corner, visible at the top of the preceding Times Tower photo. The color and square cross-section of the slats echo those of Piano's earlier projects. In this house, the screen's openings correspond to operable windows within the underlying glass curtain wall. As with Stone's town house, a device from a much larger project is adapted to a residential scale.

Designed by the Japanese firm SANAA (Kazuyo Sejima and Ryue Nishizawa), the New Museum of Contemporary Art at 235 Bowery was completed in 2007. Above its street-permeable first floor, the building adopts the sculptural motif of a stack of offset white boxes, creating a distinct logo while allowing for skylights, terraces and galleries of varying proportions. Intrusion of windows on the overall sculptural effect is reduced by way of a continuous mesh that extends over both opaque and glass surfaces. A double-reading results; windows have a ghostly legibility while the mesh supports the illusion of a uniform surface. SANAA's projects often use windowflage, with techniques ranging from superimposed screens to fritted glass to deliberate dislocation of windows from conventional grid patterns.

The New Museum's screen is an enlarged version of the expanded metal mesh that is conventionally used as lath for plaster.

The mesh lends the museum's blank surfaces a texture, depth and responsiveness to light, even as it camouflages the building's few upper-story windows.

41 Cooper Square, Cooper Union's new academic building, was designed by Thom Mayne and his firm Morphosis. Like the screen of rods at Renzo Piano's Times Tower, its perforated stainless steel veil opens up to selectively reveal underlying glass while unifying the upper floors. Mayne has used perforated steel and telegraphed windows through it in earlier projects, including his 2001-04 Caltrans Headquarters in Los Angeles. Unlike the Times Tower or Caltrans, 41 Cooper Square uses its screen to break free of rather than reinforce the rectilinear, and indulge in something closer to pure sculpture. Here Mayne explores new territory with the plastic potential of the screen.

A close-up of 41 Cooper Square's perforated steel screen shows how its accents are created by leaving some holes filled in. The image shows how such screens gray-down colors, despite claims that they are transparent. The less open the screen and the dimmer the exterior light, the more the world seen through the screen appears in silhouette. The retina's shape-perceiving rod cells are more sensitive than its color-perceiving cone cells; when stimulation is evenly reduced, form perception suffers less than color perception.

Its free-form screen gives 41 Cooper Square the rich visual variety of sculpture as one moves around it.

For the cover of last November's Architectural Record Magazine (photo: Roland Halbe), 41 Cooper Square poses with its screen's "windows" open. The layering of a screen with window-like openings over actual windows, pioneered by Renzo Piano, is here taken a step further; screen panels can be opened and closed just like a traditional casement window to allow clearer views out and additional natural light in, while adding life and variation to the façade. Since the building's completion, however, the screen's windows have rarely been opened.

Nearing completion at 524 West 19th Street, Metal Shutter Houses, a condominium designed by Shigeru Ban, will have inner glass faces that fold up against the apartments' double-height ceilings, and outer faces of perforated rolling shutters that provide shade and privacy. Like Mayne's screens, Ban's will be operable. Unlike those at 41 Cooper Square, Ban's are likely to be opened.

The perforated rolling shutters of Ban's project are off-the-shelf security technology familiar from the corner bodega, and characteristic of the architect's ad hoc use of humble materials like cardboard tubes and shipping containers. Their densely packed perforations will provide privacy, allow cross ventilation, and keep bugs out, at least in theory.

In addition to their practical purposes, Ban's perforated shutters will also provide the veiled transparency required of today's sophisticated windowflage.

Smith-Miller+Hawkinson Architects presented this design for the Great Jones Hotel at 25 Great Jones Street to a public hearing of the Landmarks Preservation Commission last week. According to the website Curbed, "The Landmark Committee is urging Smith-Miller to re-work the perforated stainless steel skin (complete with sexy leaves pattern) into a tripartite look, hoping to minimize the building's verticality and create a structure that's a more contextual companion to its neo-classical neighbors," which would entirely miss the point - and historic local pedigree - of this school of windowflage.

A model of the Great Jones Hotel shows two types of windowflage: the front facade has a perforated stainless steel screen with a truly camouflage-like pattern etched into it, while the side wall has punched windows that are freed from the usual grid to disguise themselves as a free-form pattern from a Suprematist painting.

A pre-war brick office building at 1775 Broadway is currently being wrapped in a glass curtain wall, part of its repackaging as "3 Columbus Circle." The new look is the work of Gensler, the world's largest architecture firm. A rendering posted at the job-site, below, suggests that the original punched window openings will be visible through the new glass skin. This would follow the trend for layered windowflage, adding a sculptural unity without entirely suppressing underlying diversity. It would also distinguish the project from deeply regrettable precedents like Donald Trump and Der Scutt's 1980 tinfoil mummification of Warren and Wetmore's 1919 Commodore Hotel into the Grand Hyatt, just east of Grand Central Terminal. The emerging reality of 3 Columbus Circle, however, shows the rendering's visual depth to be as fictional as its prairie setting. Other recent projects pursuing a layered effect by this means, like 15 Union Square West, have fared no better.

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