I have been looking at a lot of auctions and dealers and what I really noticed is the immense difference in patina color of coins, including coins of the same type. What I also noticed is that some dealers have a lot of bronze (Greek) coins of totally different types and area's for example Ptolemy, Seleucid, Tarentum, Macedon etc. and all they have the same patina color, for example in one case black to very dark brown, but no other than that. I really fail to understand this, first of all how come that coins made in the same region during the same time period have such a big difference in patina color? Second I don't understand how some dealers have coins from different time periods and regions and all have the same patina color? Where do those dealers get their coins that they all have the same patina color? For example this dealer has coins from all different places and time periods but all have the same patina color: Bruttium SYRIA Seleukis LYDIA SARDES Thrace Lysimachos CARIA RHODOS
Soil conditions in a given area can lead to some consistency in patina of ancient bronze coins, or so I hear, but you might find this thread informative: https://www.cointalk.com/threads/from-a-to-z-and-orange-to-yellow.290945/ Edited: The pictures you added to the post look perfectly fine to me! Nothing unusual about the patinas. That's a nice group of ancient bronze coins.
