The term
‘intuitive’ is used by analogy with computer interfaces which are said to be
‘intuitive’ if they give the user control of relevant variables in an obvious
manner. The Intuitive Colorimeter is ‘intuitive’ in so far as it allows
the user to vary colour on the three intuitive dimensions of hue, saturation
and brightness.
The instrument
provides colour and is therefore, technically, a ‘coloriser’. The term
'colorimeter' is usually reserved for an instrument that measures colour. The Intuitive
Colorimeter measures the colour optimal for reading, and may, in this sense
at least, be said to be a colorimeter as well as a coloriser.
The Intuitive
Colorimeter exists in four versions, the original Mark 1 version,
and three later versions Mark 2 , Mark 3
and the Curve,
which have now superseded the Mark I. The later versions differ
from the original (Mark 1) with respect to the way in which coloured light is mixed to provide the
required shade. In these later versions the spectral power
distribution of light from the instrument is the same as that obtained under
conventional lighting when coloured glasses are worn. The instrument can
therefore be used by individuals with anomalous colour vision.
Tinted
trial lenses are used to ratify the colour chosen with the Intuitive
Colorimeter and to refine the tint, where necessary. The lenses are
calibrated and specify the tint prescription for use in glasses. The Intuitive
Colorimeter Mark 2 and 3 are calibrated instruments, and there is a
particular combination of trial lenses that matches any given setting. Software is
available that can be used to obtain this combination, and provide information
about the tint.