From a reader:
I just had a quick question: If a seminarian or anyone for that matter wears an an alb at Mass is it proper to wear an amice under it? I have a cassock and surplice but the "tradition" in my diocese has been that seminarians wear albs when sitting in choir at Mass or serving or whatever.
For the Novus Ordo, the general rule is that street clothes should be covered. For clerics, for sacred ministers, that sometimes requires the amice if the alb is not constructed so as to cover the collar.
If you priests or deacons in Mass vestments with their Roman collars showing, they are under-dressed.
As far as lay people are concerned, I think the rule would still apply.
But I wouldn’t want the use of an amice to lead to any sense of "clericalization" of the lay people who use them. If there must be servers in albs, perhaps it would be better to have those albs that entirely cover the next, thus eliminating the need for an amice.
Seminarians should use proper choir dress. But if they are forced to use albs, then use the amice if necessary to cover street clothes.
For the Usus antiquior, priests must use an amice. Servers would be in cassock and surplice.
His omnibus scriptis: If you don’t have an amice and one isn’t available, you go ahead as best you can without it. You are not held to the impossible. But be responsible beforehand and make sure you have what you need. Don’t assume these days that parishes have amices unless they also have more traditional liturgical worship.