Hi is it possible to tell if someone was left or right handed from a picture of their handwriting alone?
If you're relying on one case of a person's handwriting, I'd say no.
Writing can depend on the angle of the paper, type of pen etc.
I've known left handed people to write completely differently - sloping in opposite directions.
I'm right-handed & depending on the situation I'm in, what I'm writing, how the paper is positioned, my writing can slope in either direction or be straight with no real slope.
I don't think you can rely on 1 case.
You don't state an era i.e. do you have their signature on any marriage, births or deaths?
Annie