Spectral index profile (α) along the jet ridge line of 3C 452 measured from four frequency pairs 4.9/8.4 GHz (black triangles), 8.4/15.4 GHz (blue squares), 15.4/23.6 GHz (green diamonds), and 23.6/43.2 GHz (red circles). The horizontal axis shows the projected distance in milliarcseconds from the common reference frame, and the vertical axis shows the spectral index computed via S_ν ∝ ν^α. The central region (within ∼2 mas) displays strongly inverted spectra (α > 2), which are indicative of synchrotron self-absorption, while downstream values turn negative, consistent with optically thin synchrotron emission. The peak in the spectral index near 0 mas supports the adopted reference position of the black hole.