Heat only patinas (harlequin colors) are by nature transient. If you
want more stable and more repeatable colors, the use of different
chemicals are in order. There are fumed, buried, cold and hot
patinas, with many variations of each, and everything giving
different looking results. Do a Google search for "bronze patinas"
and you will fine gobs of I very much like Patrick
Kippers book "Patinas for Silicon Bronze". I use it as a resource,
idea book and as examples for clients or students. The formulas work
unlike some "coffee table" look pretty but poor books.
Ron Young at
has written an ok book, but he does sell proprietary patina mixes a
well as some other patination materials. Triple S "SSS" chemicals in
Los Angeles is another source for larger quantities of chemistries
and a lot of the "base" materials. Your local sporting goods or
hardware store often have "gun blueing" materials that will/can work
on bronze but not always as the instructions say on the bottle as
these materials are normally for steel and you are applying them to
Professional patinators are, like most any experiences professional,
highly sought after by art foundries. This is not to infer that you
or anyone should not attempt patination, it is just that these folks
can repeat coloration for a series, and they generally have a few
secrets up their sleeves.
If you or anyone need any further help with coloration of metals
(for me I do copper) I would be happy to help if I can.