and yet the decrees, papal documents, etc. regulate explicitly the color of the pompom. no bishop would use a biretta without it. careful with vestimentary revisionism.
where does one get a nice roman, non-folding biretta?
Just to to Gammarelli and they can make whatever you want.
Wippells in England make beautiful birettas
Interesting that being a Roman biretta, one cannot find them "in stock" in Rome. As the person said above, you have to go to Gammarelli and have them make you one. I have one on the way.
Wippells birettas are, I fear to say, distinctly non-Roman in shape !The one in the photo is also, sadly, rather higher in the centre than was really traditional in Rome.However; the answer to where to get one is to do as Seminarists had to do in olden days when they first arrived at the Seminary : make your own ! (Takes about two hours, and costs peanuts.)
Large stock in many sizes held by Barniconi in Rome