Cast bronze plaques can be finished with a paint or finished with a chemical patina with a variety of different effects. The natural color of bronze is actually a very light gold, but the common belief is that bronze is actually a darker brown. Most people only see bronze sculptures after a patina has already been applied, which is what makes people think bronze is naturally a dark colored metal.
A patina can occur naturally over time on the surface of most metals, caused as a result of oxidization, age, or exposure to changing weather and environment. Patinas can also be applied to metals when they are produced, which prevents weathering and general wear and tear on a plaque and also makes the plaque more visually pleasing.
What is important to note is that a true patina, whether it occurs naturally or is applied, chemically changes the surface color of the bronze. It will not peel away; it will not chip off. Plaques that are finished with paint and not patina, can have adverse chipping affects because the paint simply sits on top of the metal. With heavy foot traffic, the patina color will change and naturally burnish and shine, but this creates a pleasing look and gives the plaque a true luster, rather than a painted plaque that just looks badly maintained.
Often times other plaque companies will use the word patina or stain without actually using the true chemical process to color a cast bronze plaque. Applying patina to a bronze plaque is a more expensive process than what most plaque-makers want to use. Many companies use other products with names like chem-col, polychrome patina, and graphite sprays, which are really just paint. If the bronze work is set in a horizontal position, or is subject to extreme weather conditions, these other products will start to peel in a few years.