pranimaboity2050

After going through diffraction and interference pattern(theoretical) due to a double slit I am wondering although the set up is same why are the patterns different.is it because for diffraction to take place the slit width needs to be comparable with the wavelength of light?? What do you think?
Also if I perform double slit diffraction with white light instead of monochrome I am supposed to get principal maxima/central band white and the secondary maximas spectral.What about the interference fringes inside the central maxima? Will all of them be white?or only the centre most one will be white and the rest spectral?