Please let me give you some details:
My Workflow and Setup:
I shoot tethered Raws directly into C1 Pro 5.1.1. I than send processed Tiffs (16bit, ProPhoto RGB) @360ppi for an Epson large format printer, to PS4 for soft proof, output sharpening and print.
In order to fit the 4:3/645 ratio images on paper, I need to change their output size. As I fixed the ppi# at the optimum 360 for Epson, I do use the SCALE function in the C1 process tab. Maybe it is better to do that in PS4?
Thanks in advance you for your insights and thank you FredJeanG for promptly sharing your practices.
My perspective has always been to test and experiment - easy enough to do. Try scaling in C1, then try in Photoshop, then print and compare. C1 scaling is pretty straight forward, while scaling in Photoshop (and of course other programs) may have particular techniques that enhance or detract. My view is that as Photoshop goes from version to version, effective scaling algorithms may change, procedure for effective scaling may change (for instance scaling in thirds or tenths). And the same could be said for Capture One from version to version - it may not necessarily be documented.
My thought at one time was that scaling in raw would always yield a better result than scaling a processed tiff. But one day a test of that (in an unnamed digital back raw program) revealed that the scaling algorithm in the raw software was quite poor and Photoshop did a much better job.
Print and compare - best method, IMO.
There are others who truly specialize in scaling that I'm sure can offer more insight.