Increase of water content in a mixture leads to quenching of fluorescence, and increase in 605 nm band (at 50% water content, peaks at 537 and 605 nm have almost equivalent intensities). Spectra at Figure were normalized to sum intensity of two observed maxima for clarity purposes. Absorption spectra demonstrate no sharp aggregate maximum, and the only actual difference is in vibronic shape due to aggregate formation. Figure : Changes in fluorescence spectra, normalized to sum of intensity maxima: left -upon solvent content variation, right -upon BODIPY-C18 concentration variation.