Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
Lightness and Brightness and Other Confusions
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
of the sky). This is denoted by visual concepts such as surface colour, volume<br />
colour <strong>and</strong> film colour. (Katz 1935).<br />
A surface colour is perceived as being part of the surface only. One example is<br />
an opaque paint surface. A volume colour is perceived as permeating the<br />
whole volume of an object or substance. Examples of this are coloured glass,<br />
gas, mist <strong>and</strong> water. A luminous colour is perceived as belonging to a shining<br />
object, such as a light source. Here it is important to remember that these<br />
concepts are visual <strong>and</strong> phenomenological, they describe what we see <strong>and</strong> not<br />
the underlying physical cause. For example, in pictorial art, the painter can<br />
create the experience of light by skilful use of contrast – <strong>and</strong> those spots on<br />
the canvas are, as perceived, luminous colours. 53 (Fig. 9)<br />
Figure 9. This colour combination is an expressive symbol for the contrast<br />
situation perceived in shining <strong>and</strong> self-luminous objects, such as a lamp in<br />
darkness or light through an opening. (See Natural Experience, pp. 26, 30).<br />
The middle part of the figure is a luminous colour in Katz's sense.<br />
(Illustration: Ulf Klarén)<br />
The visual properties of a colour can be described with words such as hue,<br />
value, nuance, etc. Several of these terms are ambiguous <strong>and</strong> thus not scientifically<br />
usable unless they are further defined. 54 NCS (Natural Colour System)<br />
is a coherent system for colour description, based purely on visual assessment.<br />
It categorises the perceived colour in comparison to perceptual<br />
st<strong>and</strong>ards that are understood as inherent to the human visual system. The<br />
elementary colours yellow, red, blue, green, white <strong>and</strong> black are defined as<br />
having no similarity to any other colour than themselves. Hue is, according to<br />
the NCS, the specific colour’s relative similarity to the chromatic elementary<br />
<br />
Gilchrist et al. 2007 ; Fluorent or luminous colours are discussed in da Pos 2005. For<br />
a further discussion about visual categories such as transparency, depth, translucence,<br />
etc. see Fridell Anter 2006, p 142.<br />
<br />
The confused use of some of there terms is discussed in the article <strong>Lightness</strong> <strong>and</strong><br />
brightness in this volume.<br />
51