For reproducible preconditioning or saturation, the solvent is initially only filled into the trough opposite the plate; the preconditioning with the superplasticizer is carried out for as long as desired. Developer solvent is in the tub opposite the platen. The preconditioning can be carried out with any solvent and for any duration. The separation process begins with the introduction of the solvent into the trough in which the plate is located.