Scatter plot of the apparent flux density B_6302.5 for the 6302.5 Å line, derived from the measured Stokes V assuming intrinsically weak fields, vs. the corresponding quantity B_5250.2 for the 5250.2 Å line. The data are taken from two consecutive full-disk magnetograms with about 100 arcsec resolution in these two spectral lines, recorded with the STOP telescope of the Sayan Solar Observatory on March 26, 2012.