Color–color diagrams in the F450W − F555W/F606W vs. F450W – F814W filters of the cluster candidates in both galaxies. Top panel: NGC 3808B stellar systems (the PRG) are shown with circles and the candidates in NGC 3808A are indicated with squares (the gas donor galaxy). The assumed metallicity (see Sect. 2.6) for NGC 3808B, Z = 1 Z_⊙, is shown with a solid line. Bottom panel: NGC 4650A cluster candidates are shown with blue solid circles, and the isometallicity track (Z = 0.2 Z_⊙) is plotted with a solid line. For comparison, we show with dashed line a metal-poor SSP of Z = 0.02 Z_⊙, typical for an old cluster. We indicate a few ages along the SSP tracks with labeled crosses.