Manuscript Preparation, Copyediting, and Proofreading

Q. We are editing a scientific book. We have to follow UK spelling. Per the dictionary, sulfur is the US spelling and sulphur is the UK spelling. But in one chapter the author has used sulfur and in another chapter sulphur. Since we are following UK spelling, can we change sulfur to sulphur? Or, per CMOS, since the IUPAC recommended spelling is sulfur irrespective of UK or US spelling, can we change sulphur to sulfur?

A. Good grief. You can’t lose—just pick one.