visible light - What is difference between white objects and transparent objects as far as photons are concerned?

Transparent materials let photons through because the energy gap of electron is so large that the photons cannot be absorbed. If the material absorbs a photon, the photon disappears; does this mean that its appearance is opaque? How about the colour white? In this case, does the material absorb photons?? Because white materials seem opaque most of the time.