According to Padraigin Ni Uallachain, singer, writer, folklorist, historian, wife of Len Graham, and native Irish speaker;

"The dyeing of petticoats indicated that the woman indicated herself as betrothed: it was a sign of loyalty to her absent lover".

She also says that the song is a Jacobite one, so "Johnny's Gone for a Soldier" - that is, the Wild Geese, is not too far off the mark.

She also explains all the parts of the spinning wheel, and Kim C above certainly on the right track. Padraigin's book is "A Hidden Ulster: people, songs and traditions of Oriel [south Ulster/north Leinster]". The book was published last year by Four Courts Press, Dublin, and it's a 500 page treasure-trove, worth the money for the photographs alone.