An investigation of the visual privacy obtained with two types of window treatment

Cultural factors in Libya require female privacy to be maintained. Outside the home, female must wear clothing that reveals only their face and hands. When inside the home and located near windows, a similar degree of clothing cover or window treatment is required. This reduces exposure to natural daylight, with a resultant reduction in the health benefits of daylight. Females who wear hijab dresses when outside of the home expose only their hands and face, with an exposed skin surface area of only 11.6% compared with 61% if wearing Western-style summer clothing. Clothing restrictions can be relaxed when in the home, but here female privacy is maintained using window treatments and these also restrict access to daylight. Currently used window treatments in Libya (the roller blind and wooden shutter) make the interior space completely dark when closed, but when opened the interior space is exposed to the outside, which offers no privacy, and hence hijab-style clothing must be worn when inside. This thesis explored the potential of window treatments to offer enough privacy so that females of some Muslim cultures might wear relaxed clothing when at home instead of needing to wear a high level of clothing.
The first stage in this study was a validation experiment where a novel pictorial clothing scale was created to allow females to state what level of clothing is needed to maintain privacy in different contexts. The result of the questionnaires inviting female participants from three nationalities (Saudi, Libyan and European) showed that variations in the cover and tightness of clothing affect the perceived level of privacy in different situations. For Libyan women, while a head scarf and arms and legs fully covered by a jacket and trousers were the median expectation when inside the home but potentially visible to a stranger, this could be relaxed (to tighter-fitting clothing, greater degree of skin exposure) if visible only to members of the family.
The second stage was to explore the ability to provide sufficient visual privacy with two window treatments, horizontal blinds and frosted glass, varying the free area and degree of frosting respectively. The degree of privacy offered was operationalised by identification of the clothing level worn by a target behind the window treatment, the aim being to reduce identification to a chance level. Two actors were used, to consider the effect of skin tone, and two durations, to consider the effect of gaze behaviour. For observations of 0.3 s duration, only the extreme level of each treatment (horizontal blinds set to 3% free area and distortion level 20 for the frosted glass) led to chance levels of clothing identification, for both actors.