Interestingly, ratio between these two maxima upon compression remains unchanged, so they should be attributed to same fluorescent species. Intensity growth is caused by increase in their surface concentration during compression. J-dimer emission is the most probable possibility, and since geometrical constraints during compression do not influence band ratio, they should be attributed to two different electronic transitions, rather than vibronic pecularity. After bend in isotherm J-dimer formation prevents BODIPY-C18 from excited-state interactions with water and leads to a rise in excimer formation processes. Fluorescence intensity rise saturates at 95 Å2 /m, and then starts to grow linearly again after 80 Å2 /molecule, for the ultimate approval of our assumption on aggregated rafts formation.