Transparent, microscopic spider web silk fibers were used to softly intrude into the propagating path of N-slit interferograms. The resulting interferograms, with superimposed diffractive signals, were recorded using digital means and reproduced using N-slit interferometric calculations. We also show, for the first time, very slight and subtle alterations of the propagating interferograms via the soft insertion of spider web silk fibers into the intra-interferometric path. The experiments were performed at an overall intra-interferometric propagation path length of 7.235 m.