Dad In Uniform

Your dad was at the time this picture was taken an aircraftsman 2nd class equivalent to an army private, because he has no badges of rank, it looks like it was taken in WW2 although I'm not sure because the side/forage cap he was wearing ( referred to the other ranks as "the chip bag" ) was issued until the early 1950's.

This kind of photography, and it's not just printing, can be tremendously important to ones identity as an individual as one begins to learn more and more about people we thought we hardly knew.