Grace Note Accidentals

Hi, I’ve got a piece in the key of C which I’m adding some grace notes to. I’m not sure if there’s a standard notation for grace notes but I’m adding say an A# grace note that’s going to a C. Dorico puts this in as a Bb. My presumption has been that if the grace note is moving up the scale it should be marked as an A# instead of Bb, unless it was going down to say a G. Are there rules on this? How do I change how the grace note is labeled?

Hi sunny16!
You can respell grace notes as any other note… Look up for “respell” in the user guide. (depends on your keyboard layout)
As for the “rules” about the spelling, I’ll let other specialists give an opinion about it!

There is a rule (of thumb) that you add sharps in chromatic scales going up, and flats when going down, but this does not apply to grace notes. I would notate a Bb here, as the resulting interval of a major second Bb-C is simpler and easier to read than the diminished third A#-C.