When we look at a ball painted black, we can easily tell that it is a ball. The side facing the light is a little brighter, and the opposite side is darker. Our eyes read the curvature and depth of an object from these differences in brightness.

But when almost no light returns from the surface, the story changes. As the contrast between bright and dark fades, a three-dimensional object can appear like a flat black plane, or even like a deep hole has opened in its place.

That is why Vantablack drew public attention in the mid-2010s. It was not simply a deeper shade of black. It was a surface that nearly erased the light cues that normally reveal an object's shape.

Sculptor Anish Kapoor became interested in the material. An ultra-black technology that had begun in precision optics and space engineering had become an artistic medium.

A tiny carbon forest instead of black pigment

The original Vantablack was not black paint.

Its key material was carbon nanotubes. Carbon atoms are connected into extremely thin tube-like structures, and when huge numbers of these tubes stand upright on a surface, they look like a miniature forest under a microscope.

When light hits a flat surface, some is absorbed and some immediately bounces back out. Light that enters the gaps between carbon nanotubes has a much harder time escaping. It strikes tiny structures, changes direction, encounters more structures, and is gradually absorbed.

The material does not become black by adding more black pigment. It becomes black by creating a path from which light has difficulty escaping.

Surrey NanoSystems reported that early Vantablack absorbed about 99.965% of incident light. This class of technology was originally developed to suppress unwanted reflected light in space and optical instruments. The company later developed a spray-applied version called S-VIS, but it was not a product that an ordinary consumer could buy in a can and brush on. It required a specialized application process.¹

When this kind of surface is applied to an object, even the light returning from its curves is sharply reduced, making the shape difficult to read.

Kapoor did not own “black”

Surrey NanoSystems collaborated with Kapoor, and in 2016 the company said it had granted him worldwide exclusive rights to use Vantablack S-VIS in the creative arts. The right did not apply to other industries.

Surrey described the exclusive collaboration as a practical choice. After Vantablack became widely known, requests from artists poured in, but Surrey was an engineering company and did not have the capacity to work with many artists at once. The company said it considered Kapoor, who had long worked with light and voids, a fitting collaborator for the technology.²

The controversy arose because the collaboration included exclusivity in the arts.

Online, the story became much simpler.

“Anish Kapoor monopolized the blackest black in the world.”

That is not an accurate description. Kapoor did not own the color black itself. He held the right to use a specific technology developed by a particular company in a particular field.

But the frustration of other artists was not merely a misunderstanding. What they wanted was not ordinary black paint, but access to a new material that produced a visual effect that had previously been hard to achieve. In the arts, they could not access that technology.

British artist Stuart Semple was one of them.

In 2016 Semple began selling an intensely fluorescent pink pigment called Pinkest Pink online.

There was one condition: it would not be sold to Anish Kapoor.

At first, it was somewhere between a prank and an artwork. Then orders flooded in. Kapoor responded with a photograph of his middle finger covered in Pinkest Pink, and the dispute grew.

Other artists then challenged Semple to make a very black paint that anyone could use.

He actually started making one.

And the story returned to materials science.

An ultra-black paint you can apply with a brush

Acrylic paint contains pigments that absorb light and a transparent acrylic resin that holds those pigments on the surface.

Simply adding more black pigment is not enough. If the dried surface shines, light returns to the viewer. To make a very black paint, the material must absorb a great deal of light while also suppressing surface gloss.

That is where Semple ran into an interesting problem.

Silica is one of the materials used to reduce paint gloss. Mixing in fine silica particles can reduce the light that flashes back strongly in one direction.

But silica is not a black pigment. The more of it you add, the less glossy the surface becomes, but the paint film can also become lighter.

To make black look blacker, you remove the shine—only to find that the material removing the shine can turn the black gray.

The BLACK series began as an attempt to solve that contradiction.

Semple separated the black pigment and base material of BLACK 1.0 and sent 1,000 samples of each to artists in several countries. Feedback included suggestions for new pigments and binders, along with the idea of using a transparent matte additive originally used in cosmetics. The pigment ratio was also increased. The result was BLACK 2.0.³

BLACK 3.0 took a different approach.

Semple said he worked with a U.S. laboratory to develop a custom pigment in which black material was formed on extremely small ceramic microspheres. Instead of using a conventional pigment and then adding something to reduce gloss, the aim was to create black particles that reflected less light from the outset.

But a better pigment was not enough. More pigment also required more acrylic resin to hold it in place. Semple said the acrylic polymer acting as the binder was also designed to accommodate a higher pigment loading.⁴

Culture Hustle describes BLACK 4.0 as a formulation combining its own black pigment, an acrylic binder, and matte additives. One product description claims that it absorbs about 99.8% of visible light.⁵

The manufacturer's application instructions are also revealing.

BLACK 4.0 should be applied in thin, even coats. If it is applied too thickly it can look gray, and covering it with a clear varnish or resin introduces gloss and weakens the effect.

The manufacturer's description and instructions show that the paint's performance depends not only on pigment absorption but also on maintaining an ultra-matte dried surface.

Vantablack and BLACK 4.0 appear to pursue a similar goal: reduce the light returning from an object to create an extremely deep black.

Their methods are completely different.

Vantablack draws light into microscopic structures and makes escape difficult. The BLACK series works within the constraints of acrylic paint, controlling pigments, binders, matte additives, and the reflectance of the dried surface.

That difference follows from the premise Semple set when he began the project. In one sentence, it was this:

“Anyone (except Anish Kapoor) should be able to buy it and apply it with a brush, without specialized equipment.”

Making a $2 million diamond disappear

A few years later, the controversy gained an intriguing epilogue.

In 2019, when MIT announced what was then a record-setting ultra-black carbon-nanotube surface, artist Diemut Strebe, who was working at MIT, collaborated with the research team to coat a 16.78-carat natural yellow diamond with the material.

Its estimated value was about $2 million. The work was exhibited at the New York Stock Exchange.

Diamond and carbon nanotubes are both made of carbon, but their atomic arrangements and structures are different, so their optical properties are dramatically different as well.

Covered in black carbon nanotubes, the diamond lost its sparkle and three-dimensional appearance and looked like a small black hole.

The work was titled 〈The Redemption of Vanity〉.

Strebe and the MIT team made one more point. They said they would not make this ultra-black process exclusive to a particular artist, but would open it to artists who wanted to use it.⁶

The numbers, however, still remain.

Vantablack is associated with a 99.965% figure, and BLACK 4.0 is described by its manufacturer in one product listing as absorbing about 99.8%. Other ultra-black paints such as Musou Black come with their own numbers.

So is 99.965 necessarily blacker than 99.8?

To answer that question, you have to look first not at the number, but at what light was measured, under what conditions, and by what method.

Continued in Part 2

Notes

1. The 99.965% absorption figure for early Vantablack and its vertically aligned carbon-nanotube structure were checked against official Surrey NanoSystems materials. The description of S-VIS as using a non-aligned CNT structure and optical cavities, being spray-applied, and not being sold like ordinary paint comes from an interview with Ben Jensen. Surrey NanoSystems · WIRED

2. In 2016 Surrey NanoSystems said it had granted Anish Kapoor worldwide exclusive rights to use Vantablack S-VIS in the “creative arts,” while the restriction did not apply to other fields. The explanation that the company had capacity to collaborate with only one artist and chose Kapoor, along with Ben Jensen's statement that it had “licensed the technology, not the color,” is based on WIRED's reporting. Business Standard/PTI · WIRED

3. The account of Pinkest Pink, Kapoor's middle-finger photograph, the distribution of 1,000 samples each of BLACK 1.0 pigment and Superbase to artists for feedback, the limitations of silica matting agents, and the use of a transparent cosmetic matting additive in developing BLACK 2.0 is based on Adam Rogers's reporting for WIRED. WIRED

4. The description of BLACK 3.0's custom black pigment based on nanoscale ceramic microspheres and an acrylic polymer designed for high pigment loading comes from a 2019 interview with developer Stuart Semple. It is the developer's account, not an independent composition analysis or peer-reviewed paper. The Naked Scientists

5. The description of BLACK 4.0 as using black pigment, an acrylic binder, and matte additives, along with the 99.8% absorption figure, comes from manufacturer Culture Hustle. Its current FAQ says “over 99%.” Instructions on thin application and preservation of a matte surface were also checked against manufacturer materials. The 99.8% figure has not been independently verified under the same wavelength, angle, and instrument conditions as Vantablack. Culture Hustle product description · FAQ

6. 〈The Redemption of Vanity〉 was a work by Diemut Strebe and Brian Wardle's MIT research team in which a 16.78-carat natural yellow diamond, estimated at about $2 million, was coated with CNT ultra-black material and exhibited at the New York Stock Exchange in 2019. MIT explained that the diamond and CNTs are made of the same element, carbon, but have different structures and therefore sharply contrasting optical appearances; the team also said the process would be open to artists who wanted to use it. MIT AeroAstro · MIT CAST