three additional points:
1.
OTOH, if "The diffraction is quite weak", one may be limited by
counting
statistics. This also cannot be overcome by processing.
As JIm suggests above then, maybe you should look if the 15% Rmerge is
almost reasonable given the specific I/sigI at low resolution?
2. If there is one thing I do not like in XDS, is that there is no (or
I have failed to find) statistics of I/sigI and Rmerge as function of
image.
Have a look at the SCALA output. Maybe some images are bad?
3. making too fine slices of too weak diffraction images ends up with
either too weak counting statistics or inability to 'lock' the
refinement.
we did that for one crystal form, collecting 0.1, 0.2, 0.35, 0.5, 0.7,
1.0 from various crystals (with the same dose per degree, at SLS using
a PILATUS, mosaicity 0.4-0.6) in an attempt to get better Se signal.
We miserably failed to get any useful signal at the end, but learned
that for these very weak diffracting plates (submicron) collecting
0.5-1.0 degrees was actually giving at the end better data.
A.
