Re: [ccp4bb]: difficult crystal diffraction

[David W Borhani]

Try reindex:

reindex hkl h, k, l + 1
(or, e.g., reindex hkl h, k, l - 1)

It's quick & easy to do the reindexing (followed by sortmtz, then scala) to see if that is the problem. If that fixes things, then do take the longer route (in my experience) of figuring out where the beam center really is, as Bart suggests.

I had a crystal once where I had a cell similar to yours and was misindexed by 1 on the long axis. The signs from mosflm were very subtle indeed that the crystal was misindexed, whereas scala emphatically said "NO!", does not merge. Upon getting the correct beam center, the mosflm statistics did (marginally) improve, and scala then said "YES"!

Dave