All files contain raw experimental data representing evolution of the wet spot in time

The header (and the file name) explains the materials and parameters of particular experiments shown, after development, in Fig. 6: 

(a) the paper porous material used (Watercolor, Filter or Epson paper), 

(b) the liquid (neat TBP or TBP plus PSBMA), 

(c) the impact velocity (u=0.2 m/s or u=3.1 m/s) 

and 

(d) the visualization chemical, Blue or Red oil (Dye), that is BD or RD.

The first column is time in seconds (s) and the second column is an averaged diameter of the spot in (mm).

Note, the time intervals between the measurements were not always regular.