I'm posting this for future searches as I wasn't able to find this answer myself while searching this forum. So, I like DR K3 coated strings, but couldn't really figure out the difference between Black Beauties and Dragon Skin. On paper they appear to be the same thing (round core stainless) but you'll find numerous threads here claiming that they sound different, are coated differently, and with varying conductivity. I know at some point Black Beauties were nickel, but now they're stainless, so that further muddies search results given how long they've been in production.
With that in mind I just called up DR and asked them directly. In their own words, the strings are exactly the same, there is just black dye added to the coating for the Black Beauties.
So there you have it. I'm not saying there aren't sound differences that some fine-tuned ears can pick up (some claim Black Beauties sound "darker"), but according to DR there shouldn't be and they should sound the same.
With that in mind I just called up DR and asked them directly. In their own words, the strings are exactly the same, there is just black dye added to the coating for the Black Beauties.
So there you have it. I'm not saying there aren't sound differences that some fine-tuned ears can pick up (some claim Black Beauties sound "darker"), but according to DR there shouldn't be and they should sound the same.