Today being Ash Wednesday is, of course, the day for the ritual imposition of ashes on the heads of the faithful to mark the beginning of Lent. This year it is going to be a bit different. Social distancing means fewer will feel able, or wish, to attend church. That is regrettable but understandable. In addition the Holy See says the ashes should be sprinkled on the head rather than imposed on the forehead, which will be unusual to most Catholics and Anglo-Catholics in this country.
I came across, or an algorithm brought to my attention, an article about the sacramental custom and the difference in practice between sprinkling and smearing on the forehead. It is from The Pillar and sets out the variations between differ countries as to sprinkling and contact imposition, by hand or by a stamp. It shows that the origins of the various methods are not known and no definitive explanation of the variation in practice appears possible.
The article is at On Ash Wednesday, some ‘trace’ and some ‘sprinkle’ — But why?
Nota bene: The source of the article is The Pillar which is orthodox Catholic and not to be confused with a journal of the same name published in connection with The Restored Church of God, which is a heterodox group.