It is striking that the roll lengths (in meters) stated in the DUCA book are in each case almost exactly twice those of the actual DUCA playback rolls. The photo shows DUCA roll no. 10 “Murmelndes Lüftchen”. Roll length in the catalog: 21.5 m. Actual length of the perforated section of the playback roll: 10.75 m. As experts have already suspected, it can be assumed that the recording rolls were twice as long and could therefore record more finely. In the transfer via the master roll to the playback roll, the length was halved.