I edit raw (Nikon) files in CR, then click the Open button (I think that's what it is - bottom right corner) to open them in PS for further processing.
I have noticed that, when doing so, the file name shows .NEF, suggesting, to me at least, that it is still a raw file. It is only when I then later do a "Save As" that .TIFF appears as the suggested format. Does this mean that the pre-"Save As" edits are done on a raw file in PS?