I look at it this way... As far as patina and toning go; I don't care if it happened over a hundred years or took ten minutes in a hotel bathroom. If it looks natural and "market acceptable," it's OK. That said, while a little shiny, yours looks OK to me.
If someone was going to fake a patina, I don't think they would have left the bright red spots. It's probably natural, but it looks like it might be covered in Renwax or something like that.
I agree with Insider on this issue, with some caveats. I've had a number of bronze coins which had some type of colored wax or makeup applied. I think that can be harmful to the coin (based on the underlying metal once I removed such applied patinas). I prefer to avoid coins with applied patinas. There are many many formulas for patination of bronze. I suspect some of these thick uniformly green bronze coins have had such treatments. That doesn't mean I will pass one them. Some bronze patination recipes could be harmful to the overall fabric of the coin, so I am always at least a little concerned with how a given bronze coin was "conserved" prior to me owning it. I routinely treat most of my bronze coins by removing any wax or applied substances, soaking/drying, and application of VerdiCare. As for the the OP coin, it looks genuine to me. As for the age of the patina, who knows, but I'm leaning towards old/real, subsequently sealed with Ren Wax.
Very difficult to tell from a photo, really. Many base metal coins are repatinated. That is the nature of the business. I currently have several coins on my desk which are EF but look like crap patina wise. If I sell them as is they would realize $10, but repatinated they will sell for $150 easily. What to do? I dont alter coins in any way. I pass them on. I just listed some sestertii on Ebay in this manner. High grade, but ugly patinas. They will likely realize pennies on the dollar.
I agree with Ken about repatination. I think it's unethical. It's not part of the original coin. The same with resilvering an antoninianus; dishonest. Even if you have to strip off an ugly patina, say, to remove encrustation, the coin will repatinate by itself over time. Fake patinas are applied solely for the purpose of deceiving a customer and making a quick buck.
