Thanks for posting HH’s picture here, however, this was probably brought from India - the Malankara/Syriac Churches don’t particularly have a Liturgical color sequence (although lately, some are following some of the Byzantine tradition, especially those who have attended Byzantine seminaries), except for the common, but not universal black (rubric is ‘penitential/simple’ not a color) for the Great and Holy Friday of Crucifixion.
The colors are “happy” or “sad.”
They don’t need to be precise.
If the celebration calls for vestments in a “happy” color, then that’s what should be worn.
The point is to follow what the rubrics say.
How would this fulfill the requirement? The person that doesn’t know why the priest is wearing white can still question - ‘hey this guy is trying to show off by not wearing green like the rest of them!’
You asked the question, about a particular situation. If he has a white vestment, that would be the best option (in your scenario).
You asked about this happening at a Latin Mass. The Latin rubrics say that white can be used as a substitute for other colors (in most circumstances).
As I said, in that case, I would personally probably use a white vestment (rather than green) to match my guest.
There is no one answer, but different possible responses depending on the circumstances.
I don’t know, I’ve seen many combos in my lifetime. From the Pope on down to the local bishop and priest. In fact, I’d say some level of combo is the norm and a ‘strict adherence to the particular Tradition of the host’ is the exception in practice.
Remember Pope Benedict’s visit to the Melkites a few years back? How about the Latin Rite Armenian Mass by Pope Francis? Or nearly every Eastern Liturgy with Pope JP2?
In the East, the colors are not as strictly defined as in the West. Also, we don’t know the exact reasons why any one priest/bishop made a particular choice at that exact moment. I can’t comment on that.
All I can say is that in general it’s best to match the celebrant because the color for any celebration is determined by the rubrics that apply to the celebration, not the rubrics from a different ritual Church.
It is simply a matter of common courtesy and good manners to make an effort to bring the color that the host requests.
Also, we cannot look at Papal Masses for patterns because Papal celebrations are unique. Those are the only times that the various rituals actually can be mixed, because the Pope is a member of all the Churches. Papal ceremonies have their own rules that don’t apply to parishes. The funeral of St John Paul II was a good example. Different elements from the various liturgical families were combined (even though most of it was the Latin tradition). No such thing is allowed at parish (or even diocesan) services–not in the same way, and not to the same extent that happens at Papal services.
I am not saying that the color choice is a strict rule. Some flexibility, and some accommodation might be needed, especially in cases of necessity. For example, if the Malankara priest visits my parish, he might only have packed a single vestment. If he only has one, then he wears what he has. If he is visiting from his own parish 15 minutes away and he has access to a full closet of vestments, that’s different.
The same thing applies in reverse. If a Latin priest is invited to concelebrate at a Malankara service, he should wear what the host asks him to wear (whether that’s very specific, or it’s more general).
What concerns me is that people are under the false impression that the rubrics of “which color to choose” apply to the individual priest himself—that he “brings” his rubrics when he visits another ritual Church. That’s not how it works. The rubrics are determined by the liturgical books of the celebration itself.
But just in case… it is my understanding that vestments and liturgical color are prescribed by the rubrics. So why an exception for one and not the other?