Method

1.1 Experimental Set-up

Measurements were executed in the Visual Comfort Evaluation (VCE) set-up which consists of a 1:5 scale model of a 3.6 x 5.4 x 3 m3 office room with an artificial overcast sky, see [1]. The inner walls are matt black (RAL 9005) to exclude the influence of internal reflections on the effect of the contrast region. A hole in the long side of 0.3 x 0.6 m2 simulates the window. The wall next to the window is painted matt white (RAL 9010). All materials are positioned to the right side of the window, and if the materials were not high enough they were elevated using a piece of string, see figure 1.a.

All luminance measurements were performed with a Minolta LS-110. The top-angle is 1/3 degree. At a minimum distance of 1014 mm, the diameter of the measured spot is 4.8 mm. The measurements were taken at a height halfway between the top and the bottom of the window. On the right-hand side of the wall measurements were taken every 2.5 cm in the horizontal direction. Two measurements were taken in the transition region, and one in the window along the line given in figure 1.b.

Figure 1: Experimental set-up (a) and measurement points given in the vertical cross section (b)