When you mix blue and black, the black consumes the blue. It's a powerful metaphor for a one-sided or broken relationship, which seems to be what the song is about, although with lines like "tears on a river, push on a shove" it could also relate to a death or abuse of some kind. In a Songfacts interview with Kenny Wayne Shepherd, he said: "So many people have applied it to a death in the family, an abusive relationship, a broken relationship, or whatever. There are so many different ways. That's what's beautiful about music and lyrics is trying to write a song that the listener can apply to their own experience in whatever way seems fit. And that's one of those songs."
Shepherd wrote this with the husband-and-wife team of Tia Sillers and Mark Selby, who also composed "There's Your Trouble" for Dixie Chicks. "We wrote that when we were down in New Orleans," Shepherd told Songfacts. "I had the music, and Mark and I were just rolling with the music and tried to develop things up. Tia came up with this idea based on a shirt that I was wearing that was blue and black. She noticed the two colors that were dominant on my shirt, and if you mix those two colors together, black consumes the blue. It doesn't amount to anything if you put the two together: You still have one color, instead of creating a new color."
With this track, Shepherd became one of the few blues artists to land on the Hot 100. He never returned to that chart, but consistently went to #1 on the Billboard Blues Albums tally.
Jerry Harrison of Talking Heads produced this track and the rest of the Trouble Is... album.
Rock band Five Finger Death Punch covered this for their 2018 And Justice For None album. It was their lead vocalist Ivan Moody who wanted to record the tune. Rhythm guitarist Zoltan Bathory explained to HMV.com:
"Ivan is a big country guy. You take him to a country bar and he will be there for hours and hours. He particularly loves that song. It worked for us too, if you're a heavy metal band there is no point in covering Metallica or Iron Maiden, the song needs to be a little off, something we can make our own."
Bathory admitted to Billboard that he was initially skeptical about reworking Shepherd's tune. "That song has a Southern vibe and we don't, and we ended up recording it because he really wanted to,' he said. "It came out amazing, and I love the song, and we made it our own, which is important when you cover a song."
Five Finger Death Punch dropped a video for their cover in which the band perform the track in an increasingly strange bar. The clip was directed by Dale "Rage" Resteghini from a treatment written by Zoltan Bathory. The band selected the historic Pioneer Saloon in "Ghost Town" Goodsprings, Nevada as the background for the visual.
In 2019, Five Finger Death Punch released another version of this song, this time with contributions from Shepherd, Brian May and Brantley Gilbert, who often covered the song at his concerts. Proceeds from this version are directed to the Gary Sinise Foundation, which assists veterans and first responders. Said Shepherd: "This is a powerful collaboration of rock, country and blues artists and a true testament to the commonalities these musical styles share."