As part of the Festival of Future Nows 2017 ∞ the artist Jeewi Lee continuously sweeps the historic hall of the Hamburger Bahnhof. In sweeping the floors clean, the artist gathers and records traces of the exhibition and its visitors. In the course of four days, the sweepings—a heap of fine particles such as dust, dirt, fluff and hair—will be combined and finally blended with chalk. Chalk, formerly used by hospitals to whiten and disinfect, serves as a neutral base to distill the ‘essence’ of the exhibition and to determine its coloring. With the aid of a common color scale, the grey tone of the heap will be determined and further, the color index of the exhibition. The work will be repeated in the exact same process in various contexts. By means of the grey tones, Lee develops her own index of various exhibitions and exhibition spaces.