As far as art feuds go, the fight between Anish Kapoor and Stuart Semple is unusual—the two British artists are feuding over a color. But, this isn’t just any color. It’s the blackest black in the world, a shade so dark that it absorbs almost all the light that hits it. Dubbed Vantablack, the darkest color in the world absorbs 99.96% of the light hitting it, making any surface it’s coated with look like a totally flat black hole. Although Vantablack was developed with military uses in mind, Anish Kapoor acquired exclusive rights to it in 2016. Although he’s not the creator of Vantablack, nobody can use it but him.

Artists everywhere were outraged, and took to social media to voice their concerns. Kapoor, who is one of the wealthiest artists in the world, declined to engage. “He’s got like 40,000 Instagram followers, doesn’t follow anybody back, doesn’t write back to anybody,” Semple says. “It’s the equivalent of walking into a house party and just shouting about yourself and not having a conversation with anybody. You’d look like an idiot.”

Semple is known for his colorful paintings, which frequently make use of pop culture references. He’d been making his own pigments for years, and decided to release one to the public as a protest against Kapoor’s refusal to share Vantablack. Semple put out a pigment he called the World’s Pinkest Pink, available for just £3.99 to anyone who wanted it… except Kapoor. A legal disclaimer on Semple’s online store made this clear: “By adding this product to your cart you confirm that you are not Anish Kapoor, you are in no way affiliated to Anish Kapoor, you are not purchasing this item on behalf of Anish Kapoor or an associate of Anish Kapoor.”

But Lisson Gallery, Kapoor’s London representative, violated Semple’s terms of service to purchase the Pinkest Pink. Then Kapoor shared a photo on Instagram featuring him flipping a pink-dipped middle finger to the camera. Caption: “Up yours.” And so the feud began.

Up yours #pink A post shared by Anish Kapoor (@dirty_corner) on Dec 23, 2016 at 2:32am PST

Semple was outraged that Kapoor had gotten ahold of the pink, but their disagreement goes far beyond paint colors. For Semple, Kapoor represents an unchecked art world elitism that has finally gone too far.

“I think their generation is all about selling something for as much as possible, to as few elite people as possible,” Semple says. By contrast, Semple doesn’t make any money from selling the pigments he makes. “It’s about getting the colors out there and making them available.” He eventually decided to create his own super black. It would be crowdsourced, affordable, and available to everyone (except, of course, Anish Kapoor). It also smells like black cherries.

The demand for Semple’s Black 2.0 has been huge, and his online store quickly sold out. “My son’s sticking labels on,” Semple admits, laughing. We talked to Semple to find out more about this new, affordable blackest black, and what it’s been like to find out that one of the richest artists in the world might be suing you.

Format: Could you tell me a bit about the process for making Black 2.0? How did this project come about?

Stuart Semple: I’ve been making my own colors for about fifteen years, my own paints, to use in my work. As part of that I got really into how acrylic paints are made, and that lead me into making my own acrylic base that could hold pigment. Basically every time I’ve made an exhibition or made some new work, I tweaked the recipe of my paint, and that’s been going on for ten, fifteen years.

With the whole Anish Kapoor thing, everyone was writing to me, saying: can you make a super black? I was like, I don’t know! Probably not. Then eventually I was like, alright, I’ll have a go, I’ll try to make a super black. And I did my best and it was quite good, and that was Black 1.0. I shared it for beta testing, for artists around the world to basically tell me what they thought of it and how I could improve it. It was awesome, there were thousands of emails coming in from all these people with amazing ideas of different pigments, different chemicals. So I put all that together very quickly, and we made Black 2.0. It wasn’t really me. It was everyone who made it, all together.

What makes Black 2.0 different from Vantablack?

Vantablack is a process—it’s not really a material. Vantablack is grown on something, normally in an antigravity chamber. And the thing it grows on gets very hot because it absorbs so much light. It can go up to about 300C. They’ve made a new one now that only goes up to 150C, and they can spray it on things rather than having to grow it in the vacuum chamber. It’s still a very difficult process to apply Vantablack, and you can only coat things up to about a meter, because you have to do it in a spray booth. And then after you’ve coated them you have to bind it, so it’s a really complicated process to seal it on.

It’s also very toxic, it’s really bad for you. You can’t really export it because of military controls and stuff. So you can’t really use it in other countries. And also it’s extremely expensive. These are the things that are problematic with it. But the main thing about it is just how much light it absorbs. It’s absolutely awesome stuff, it’s wicked.