“Transparency means a simultaneous perception of different spatial locations. Space not only recedes but fluctuates in a continuous activity.”
Rowe, C. & R. Slutzky
‘Transparency,’ ‘space-time,’ ‘simultaneity,’ ‘interpenetration’: in the literature of contemporary architecture these words are often used as synonyms. However, in architecture, the transparency implies more than an optical characteristics, it implies a broader spatial order.
At the beginning of any inquiry into transparency, a basic distinction can be established. First, transparency concept may be an inherent quality of substance or second, it may be an inherent quality of organization. For this reason, it is easier to establish distinction between a real or literal and phenomenal or seeming transparency. Transparency meaning is to percept the different spatial location in which space fluctuates in a continuous activity and pleasure the spatial experience. For example, when two or more figures overlapping each other, each of them claims for itself a common overlapped part and it brings about some kinds of contradiction of spatial dimensions. Figures interpenetrate each other and it does not cause to visual damage. However, the transparency consists of more than a visual feature. It expresses a wider spatial organization. This article explains the transparency in terms of the distinction of the two types of transparency: The Literal and Phenomenal transparency.
Architectural criticizer and historian Colin Rowe and Robert Slutzky identify transparency in architecture as more than a mere visual perception of clarity but as a new psychological perception of time and space. The article on transparency in 1955 and they claim that the transparency has distinction in two main issues in that article. These are literal and phenomenal transparency. A literal transparency is conceivable as perceptual transparency. It is a quality inherent to substance or matter, such as in mesh screens, translucent walls, etc… On the other hand, the phenomenal transparency, that is, a conceptual transparency, a quality inherent in the spatial or volumetric organization. The phenomenal transparency is applied with solid material and create different transparency interpretation to architecture. A spider web can be example to understand better. Spider web is not a transparent material but it shows the things that in the background. Transparency that is composed of transparent materials, and enable to rear objects visible is ordinary and obvious. However, phenomenal transparency is a visual device to percept the different spatial locations in which space fluctuates in a continuous activity and pleasure the spatial experience.
Learning and teaching phenomenal transparency hence requires rigorous experimentation of understanding and play of various layers and planes in architectural design and phenomenal transparency is achieved in the interpenetration of these spaces. For example the
Mondrian paintings based on phenomenal transparency. It is in the painting on the left. First row (from left to right) figures shows two separate layers are placed (yellow and red), then red plane to reveal the yellow layer underneath. In second row start with blue layer and blue plane to reveal the other color layers underneath. In the last row, the all layers overlapping each other and create new spatial stratification.  Rowe and Slutzky carried to this phenomenal transparency idea to architectural buildings.
The Bauhaus building designed by Walter Gropius is the one of the most significant examples for literal transparency undoubtedly. Gropius was interested in diagonal views of the corner which display the transparent properties of glass to their best advantage. In the exterior façade, the curtain of glass that drapes over the workshop’s faces demonstrates material transparency that leaves little to the viewer’s imagination. One can perceive the glass and framing behind it, and the space behind the glass is easily recognized and also the given sense of permeability. The grid system in façade connects building’s faces and informs the viewer of the space defined.
Unlike the Bauhaus, Corbusier’s Villa Stein in Garches appears a great example for phenomenal transparency. Unlike the literal transparency, in this building, the architect provides a suggestion of what the volume of the space might look like behind the opaque walls, and the viewer is allowed to bring to mind the hidden spaces.
Transparency is not only used via windows visually, but also we percept the interpenetration of spaces. In building, several of layers are revealed like Mondrian paintings. In these layers, some of real, some imagined and some of them have feature that is perceivable easily than others.
First layer consists of the plane of the front façade starting at the second floor and cantilevered from the ground floor plane, second, the plane connecting the ground floor wall and redefined on the roof by the two free standing walls of the terrace as well as the termination of second floor windows on the side elevation, third, the plane connecting the parapet of the garden stairs and the terrace and the second floor balcony, fourth, the plane defining the rear wall of the terrace and the front wall of the penthouse, and fifth, the rearmost wall of the terrace as well as the walls below.  In there, the real surfaces and imagined create a new logical interpretation between fact and implication. Some surfaces can disclose in the horizontal axis with floors and roof.
Vertical layers that defined the interior space of the building are spaces that overlapping in series. In this building, transparency without causing any visual confusion reveals by overlapping layers and interpenetrated surfaces. Different layers that percept simultaneously bring a new perspective to architecture. With this way, opaque place is cut by shallow spaces and people can percept easily the continuity of simultaneous spaces. At Villa Stein, the ground is conceived of as a vertical surface traversed by a horizontal range of windows at the Bauhaus it is given the appearance of a solid wall extensively punctured by glazing, 
When compare the Bauhaus and Villa Stein in terms of similarities, shallowly, garden façade of Villa Stein and elevation of wing of Bauhaus’s workshop (workshop wing is a visible literal transparency example for that building). Both of them have cantilevered slab and do not allow any interruption, also both have built-in ground floor. Both of the buildings are paid attention to continuity of window at the corner. Apart from these features, there are not any similarities between them. Bauhaus workshop wing is a visible literal transparency example for that building.
From here on, Le Corbusier is primarily occupied with the planar qualities of glass and Gropius with its translucent attributes. By the introduction of a wall surface almost equal in height to that of his glazing divisions, Le Corbusier reinforced his glass plane and provides it with an overall surface tension; while Gropius allows his translucent surface the appearance of hanging from a band which sticks out somewhat in a curtain box.
To sum up, the aim of this critique is to understand the distinction of the two types of transparency is a device that forms the experience of space and subjects. Varying interpretations allow for the experience of space to be unique to each concept. I released that the distinction of both form of transparency belongs to how the viewer interacts with the design. A kinds of transparency of looking. While literal transparency is perceived and visible easily and at the same time it offers a direct and simple communication, the phenomenal transparency is abstract and hard to understand of meaning from the outside.
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