A supernova of colour
Luckily this scenario changed over the years, and latest developments in photography, in particular subfileds of computational photography such as high dynamic range imaging, allow colours to be presented in ways not possible before.
Whether or not the architect that designed this staircase took that into consideration when he elaborated this design will probably never be known.
The result however is in my opinion unmistakably attractive. The colourful structure in the interior of the staircase makes a good contrast with the otherwise aseptic look of the walls surrounding it, as if a supernova of color just occurred.