Untitled - Journal of Lighting Engineering

While there is plenty of research
regarding lighting and safety, only a few
studies focus on the issue of preferred and
comfortable night-time lighting. Boyce et
al. 10 concluded that good lighting is
perceived to be bright, even, comfortable,
extensive in area and well-matched to the
site. Preference may also be affected by the
focus of light, so that preference is greater
when light is focused on greenery than
when light is focused on parking lots and
roads 19 .
Spectral distribution may also affect
preference. There is research evidence
suggesting that the CIE Colour Rendering
Index is connected to preference, so that
better colour rendering is appreciated 20 . In
indoor environments, there seems to also be
differences in the preferred CIE Correlated
Colour Temperatures depending on such
subjective factors as gender and such
environmental factors as illuminance. In
low illuminance conditions, preferences
tend to shift towards the warmer end of the
colour temperatures scale, whereas at high
illuminances higher colour temperatures
(colder tones) are appreciated 21 . Since many
outdoor lighting studies have compared
sodium lighting with metal halide lighting,
it is difficult to differentiate the role of the
colour temperature from the role of the
colour rendering capabilities. However, we
can assume that at low illuminance levels,
lower colour temperatures are also
preferred in outdoor lighting.
In conclusion, previous research
suggests that in unfamiliar environments,
perceived safety may be connected with the
perception of the following lighting
attributes: brightness, spectral power
distribution, the focus of the light,
Lighting promoting safety and creating a sense of pleasantness
extensiveness, evenness, and glare. Pleasant
lighting may be related to brightness,
spectral power distribution, the focus of the
light, extensiveness, evenness, comfort, and
the perception that the lighting matches
well with the site. Furthermore, because
glare causes feelings of discomfort, we may
assume that it is negatively related to
pleasantness.
2. Study Objectives
Research has suggested that several lighting
attributes may affect perceived safety and
pleasantness in unfamiliar environments.
Practical lighting interventions tend to use
higher levels of brightness as a general tool
to enhance safety, whereas only minimal
attention has been paid to other lighting
factors. The present field study explores
the relationship between the perception of
five lighting attributes (perceived colour
quality referring to spectral power
distribution, evenness, extensiveness,
brightness and glare) and perceived safety
and pleasantness appraisals in familiar
suburban neighbourhoods. The aim is to
reveal the most significant connections
between the variables in near-home
environments. In doing so, the study will
clarify whether increasing the level of
brightness is the best means of enhancing
perceived safety in suburban areas. The
results will also clarify whether the same
attributes will promote both safety and
pleasantness or whether there are
conflicting factors. Furthermore, the study
will provide insights into how varying
lighting and environmental conditions
affect the connections between the
variables.
Ingineria Iluminatului 2012; 14, 2: 33-46 35