The colour impression of insulating glass can also be described with the help of physical characteristics. The reflection colours are characterised by viewing from the outside and when viewing from the inside, as well as the colours when looking through from the outside to the inside and from the inside to the outside. In the case of all four colour impressions to be mentioned, the physical perception as well as the subjective perception of the human eye are of importance. The latter is also heavily dependent on the influences dominated by the respective light and/or lighting conditions. All the aforementioned colour impressions are subject to the fluctuations which are possible in ongoing production. Absolute colour uniformity is therefore not always possible, especially with coated glasses. In particular, colour deviations can not be ruled out when using coated glasses of different origin in the same building as well as for subsequent deliveries and retrofitting of insulating glass with coated surfaces.