Lightness and Brightness and Other Confusions

conventional concepts, which can be used with rather high precision within
the profession but are almost unintelligible to others.
A scientific approach to visual experience demands attentive observations.
Pictures made for this purpose can convey what has been observed, but for
communication and analysis of the observation there is also a need for more
specific terms than the conventional or artistic ones. The concept of perceived
light denotes attentively observed light, which can be described by concepts,
such as light level, light distribution, shadows, reflections, glare and the
colour of light. These concepts, which have been specifically investigated and
presented by Anders Liljefors (2005), all denote aspects of light as a visual
experience, aspects that cannot be identified or quantified in any other way
than through attentive visual observation.
Examples of perceptual concepts related to light
Conventional and artistic approach
Dark, light, bright, illumination, shadow, highlight, reflection, mixing,
blending, morning light, dusk, haze, penumbra, harsh light, soft light,
dazzle, glitter, warm light, cool light, Mediterranean light, Nordic light,
divine light
Visual research approach
Brightness, light level, light distribution, shadow, reflection, glare,
colour of light
Perceptual aspects of ‘colour’
Like light, the word colour is used conventionally without much need for
concept definition. All humans with non-defective colour vision can broadly
agree on how to name the colours we see around us, according to conventions
and traditions within each culture. Also in literature and other artistic or
symbolic contexts a colour or a combination of colours can be described and
understood with the help of basic colour terms like red or blue or by words
alluding to a know material or situation, like sand or sunset. Just as for light,
the only way to determine whether the term is relevant for the specific experience
is by casual or attentive observations and by referring to what we see,
have seen or have indirect experience of.
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