A general model is presented to be able to understand qualitatively and quantitatively the normal potentiodynamic, galvanostatic and potentiostastic transient for the growth of passivating films on metals during their first stages of growth. For this it is presented a general picture of the differnet possible mechanisms as far as the most important general aspects that are present in these phenomena. For these general aspects it is given some physical interpretations. On these bases one of the possible mechanisms for the case of the so called continuous film theories, supposing the Hopping Motion model for the film conduction, is developed in details. This permits to show the application of the presented physical ideas.