In the project Greyness and spatial experience we have studied visual qualities in grey/greyish colours "on location" in the  - spatial - world around. We have carried out a number of observation series not only aiming to investigate variation of greyness in different spatial situations but also to develop a methodology and equipment for such studies. In this paper perception of greyness is discussed in relation to our own observations and to scientific and scholarly references. We make some basic reflections on colour in spatial context and in relation to traditional colour theory.

In spatial context colours with low chromaticness, near the grey-scale, play a more significant role than distictly chromatic colours; hence they are very important in design of built spaces, both exterior and interior. The logically balanced distribution of greyness in shadows and in surfaces against the light produces a spatial feeling of coherency, and greyish inherent colours generally form a subordinated background to colours with high chromaticness. Simultaneously greyness to a high degree conduces to differentiation of spatial experience; an over-all spatial experience of greyness normally offers subtle but distinct contrasts of hue.

In the field of colour most scientific research deals with colour phenomena as such. In focusing on colour as spatial phenomenon, colour theory can be given theoretical connection to intuitive understanding of the world around and be part of a wider field of aesthetic research.