  For photon virtualities of $Q^2 \gsim 20 {\rm GeV}^2$, the results of the
(hard Pomeron) fit in the tensor-Pomeron model in terms of the variables $Q^2$
and the virtual-photon-proton energy squared, $W^2$, provide empirical evidence
for the validity of the Color Dipole Picture (CDP). Consistency of the CDP with
the perturbative QCD (pQCD) improved parton model implies the prediction of
$C_2 = \epsilon_0 \cong 0.30$ for the exponent $C_2$ of the energy-squared
dependence in agreement with the results of the fits. For $Q^2 \lsim 20 GeV^2$,
the CDP yields a parameter-free smooth transition from $Q^2 \gsim 20 {\rm
GeV}^2$ to $Q^2 = 0$ photoproduction, in distinction from the tensor-Pomeron
model that relies on the additional parameter quantifying the intercept of the
soft-Pomeron trajectory.
