Bromoil Print. I posted this image in different colors on Kentmere Fineprint recently. I tested Foma Variant IV for Freestyle to determine how well it would work for bromoil. This is one of the tests. This was a grab shot in the musicians tent at a long-ago New Orleans Jazz Festival. I had posed as a security guard to get into the performers' area.
Are you sure that IS Muddy Waters? I saw the guy close-up many times, and I have to say, it doesn't look like him at all. He had very high and prominent cheekbones and eyes that looked almost hooded - a very distinctive face (check it out on the google). Very nice photo regardless of who it is.