  We pursue the intriguing possibility that larger-size instantons build up
diffractive scattering, with the marked instanton-size scale <rho>
approximately 0.5 fm being reflected in the conspicuous ``geometrization'' of
soft QCD. As an explicit step in this direction, the known instanton-induced
cross sections in deep-inelastic scattering (DIS) are transformed into the
familiar colour dipole picture, which represents an intuitive framework for
investigating the transition from hard to soft physics in DIS at small x_{Bj}.
The simplest instanton (I) process without final-state gluons is studied first.
With the help of lattice results, the q bar{q}-dipole size r is carefully
increased towards hadronic dimensions. Unlike perturbative QCD, one now
observes a competition between two crucial length scales: the dipole size r and
the size rho of the background instanton that is sharply localized around <rho>
approximately 0.5 fm. For r exceeding <rho>, the dipole cross section indeed
saturates towards a geometrical limit, proportional to the area pi <rho>^2,
subtended by the instanton. In case of final-state gluons, lattice data are
crucially used to support the emerging picture and to assert the range of
validity of the underlying I bar{I}-valley approach. As function of an
appropriate energy variable, the resulting dipole cross section turns out to be
sharply peaked at the sphaleron mass in the soft regime. The general
geometrical features remain like in the case without gluons.
