Dear Kyriacos,

What kind of high-resolution data do you have? 
In my experience, while Scala usually produces excellent results, it often fails miserably or even crashes due to too negative intensities in case of low redundancy data. E.g. if one does a second high-resolution scan with a high swing-out angle with little low-resolution data and friedel mates. I have not looked whether Scala could be stabilized by somehow restraining the scale factors or switching off some refinement parameters. Since we process with XDS, in these cases I use XSCALE for scaling, which does produce very good results.

My recommendation would be to process with XDS. By using the autoProc procedure from Global Phasing this is very easy, even for people who are normally not able to run a program without a GUI. You will then have to run XSCALE manually, which is again trivial once XDS had run correctly.

Good luck!
Herman

-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Kyriacos Petratos
Sent: Wednesday, March 20, 2013 6:25 PM
To: [log in to unmask]
Subject: [ccp4bb] Scaling with SCALA high and low resolution data sets

Dear All,

we have two data sets at about 0.9 and 1.9 Ang. resolution collected from a single crystal.
Integration with iMosflm seems to be fine like the scaling within each of the data sets.
When we try to merge and scale both of them with 'Scala' we get extremely high scale factors for the lower resolution images varying between approximately 30 and 200!
Do we need to pay attention to some particular options for running the program(s)?
Thank you,

Kyriacos
e-mail: [log in to unmask]