  This paper shows that the approach based on Gribov's ideas for the
photon-proton interaction, is able to describe the experimental data over a
wide range of photon virtualities $Q^2 = 0 - 100 GeV^2$ and energies $\sqrt{s}
= W = 3 - 300 GeV$. A simple model is suggested which provides a quantitative
way of describing the matching between short and long distances (between "soft"
and "hard" processes) in photon-proton interaction at high energy. The main
results of our analysis are: (i) the values of the separation parameters
differentiating the "soft" and "hard" interactions are determined; (ii) the
additive quark model can be used to calculate the "soft" contribution to the
photon - proton interaction; (iii) a good description of the ratio
$\sigma_L/\sigma_T$ is obtained ; and (iv) a considerable contribution of the
"soft" process at large $Q^2$, and of "hard" processes at small $Q^2$ was
found.
