  The study of color transparency (CT) in elastic electroproduction of vector
mesons off nuclei encounters the problem of the onset of coherence length (CL)
effects. The problem of CT-CL separation arises especially at medium energies,
corresponding to HERMES experiment, when the coherence length is of the order
of the nuclear radius R_A. Only at asymptotic large energies, corresponding to
large CL, l_c >> R_A, the CT-CL mixing can be eliminated. On the other hand,
the net CT effects can be studied in the kinematic range accessible by the CLAS
experiment, since in this case the CL is much smaller than the nuclear radius.
Using light-cone quantum chromodynamics (QCD) dipole formalism we investigate
manifestations of CT effects in electroproduction of vector mesons. Motivated
by expected data from the CLAS experiment at JLab, we predict the A and Q^2
dependence of nuclear transparency for rho^0 mesons produced incoherently off
nuclei. We demonstrate that in the CLAS kinematical region the CL effects are
weak enough to keep the photon energy at such values as to obtain maximal
photon virtualities keeping optimal statistics of the data. This has a clear
advantage in comparison with a standard investigation of net CT effects fixing
CL.
