  Photometric properties of stellar populations that evolve according to
chemical evolution models developed by Carigi, Colin, & Peimbert (1999) and
Carigi & Peimbert (2001) are explored. Models explain the oxygen abundance and
gas mass fraction of irregular galaxies NGC 1560, I Zw 18, NGC 2366, and a
typical irregular galaxy. The photometric predictions help to narrow down the
range of possible chemical evolution models. Observed colors of I Zw 18 imply
an age of 10^8 - 10^9 yr for its dominant population, while 10^9 - 10^{10} yr
is an older age preferred by the rest of the galaxy sample. Observed colors are
in general, within errors, close to predicted. There is a tendency for the
observed (B-V) color to imply higher metallicities at a fixed age than (U-B)
(equivalently, (U-B) implies younger ages than (B-V)).
