Even the simplest metal finish orpatina can be improved by understanding the basics of coloring ortreating metals. Some metals do not react at all. Leadcame strips for instance, will not take a copper sulphate patina,but will react very quickly to certain black patina. Zinc callsfor a solution specifically developed for zinc. These differences can be very frustrating to those new topatina.
Steel reacts very poorly to most chemicals, with theexception of black patina.
You can remedy this situationin one of two ways. Apply another coat of the solution. If thatproves unsuccessful, add a little water to the patina solution andrub the chemical vigorously into the metal. The metal should thendarken evenly. Brass, copper and bronze are referred to as metals of higherintegrity, and are considered the metals of choice for fine patinawork.