Hi Rob,
On 30 Mar 2021, at 01:27, Robert Oeffner
wrote: Is this a bug, a well known feature or am I simply doing something wrong?
This is certainly known (http://phenix-online.org/pipermail/phenixbb/2011-October/017772.html) - it's because when F,SIGF and DANO,SIGDANO are adjacent columns they are converted to F+/SIGF+,F-/SIGF- with Observation type: xray.reconstructed_amplitude Adding: for a in mtz1.mtz_object().as_miller_arrays(): if a.observation_type().__str__() == 'xray.reconstructed_amplitude': for i,hkl in enumerate(a.indices()): print('{:4d}{:4d}{:4d} {:0.2f} {:0.2f}'.format(hkl[0], hkl[1], hkl[2], a.data()[i], a.sigmas()[i])) to your example code shows this: 1 -2 3 12.30 4.02 -1 2 -3 4.10 4.02 0 0 -3 39.45 85.31 0 0 3 13.15 85.31 1 2 3 3.15 3.24 -1 -2 -3 1.05 3.24 0 1 2 7.35 68.42 0 -1 -2 2.45 68.42 1 0 2 48.60 1.23 -1 0 -2 16.20 1.23 Best regards, Huw