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Comment by ghshephard | Hacker News Reader

A lot of funny claims in this article,

"Vantablack's practical uses include calibrating cameras used to take photographs of the oldest objects in the universe. This has to be done by pointing the camera at something as black as possible."

Just covering with a lens cap would seem to be a simpler way of accomplishing that,

and:

Stephen Westland, professor of colour science and technology at Leeds University, said traditional black was actually a colour of light and scientists were now pushing it to something out of this world.

"Many people think black is the absence of light. I totally disagree with that.

Really? I can't think of any better way of describing black.

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> I can't think of any better way of describing black.

That's probably the most precise and scientific definition of true black, but it's not how most people imagine a black material.

Any black material you'll encounter in everyday life is still quite reflective in comparison to this high-tech, superblack material. If you see a man in a black suit, you can still see the buttonholes, the lapels, the wrinkles, and the three-dimensionality of the man's body. That's because it's actually reflecting a lot of light.

But if the suit were sufficiently light-absorbent, you wouldn't see any of that. It would look like a homogenous blob of solid color--just a silhouette. One can simulate that experience to a certain degree with photography:

https://atowninblackandwhite.files.wordpress.com/2010/10/big...

In person, one can also get a sense of that by looking at an extremely high-contrast scene, e.g. a person in a black outfit with strong backlighting. But such a picture feels much more natural to us than would a suit of true black in a room with normal lighting.

"Really? I can't think of any better way of describing black."

I suspect the quote got mangled to suit the article. He was probably referring to the fact that since "black" is generally still reflective, it therefore must have some color. We may not be able to see it, but it has something. I'm sure we've all had the experience of seeing something that was "black" become "navy blue" in the sunlight or something.

This substance is much closer to "black", and given the mechanism by which it is working it is plausible that the remaining light is essentially reflected without preference, in which case it would technically be a black mirror, which could not be said to have a color in the usual sense of the term. (While, again, I'm sure we've all seen shaded mirrors, we do not tend to call perfect mirrors "white".)

http://en.wikipedia.org/wiki/Black_body

If something is perfectly black, then that means that the radiation it is emitting is a perfect black body spectrum, unadorned with spectral emission and absorption lines. If you were to raise its temperature to 4000K or so, it would emit white light, but it would still be "black".

This feature would indeed make it useful for calibrating equipment, as the radiation emitted from it would be very predictable, depending on its temperature.

I'm talking about color strictly from the human eye perspective, which I may not have spelled out but ought to be clear. Black body emissions into the visible spectrum at room temperature are insignificant. If that were not the case, nature would probably have chosen a different "visible spectrum".

Not necessarily. I can imagine it would be a remarkably useful trait for an organism to be able to see far infra-red, where everything is glowing. See in the dark!

Aren't you just the argumentative one?

I think it depends how absent light can be. In most blacks, its not entirely absent. What they are saying is that this black is the blackest so far, in that it creates the condition of near total absence of light - not easy, on this planet.

Interesting that its conductive qualities are so special .. I guess this means its the hotblack of all blacks. A kind of blackest of black. Or to put it lightly, black on black.

It’s the wild colour scheme that freaks me. I mean, when you try an’ operate one of these weird black controls which are labelled in black on a black background, a small black light lights up black to tell you you’ve done it. What is this? Some kind of intergalactic hyper-hearse? - _H2G2_, Zaphod describing Hotblack's spaceship

The first one would be a ham-fisted reference to a black-body reference body for determining z for extra-galactic objects. This is not it - nor is a lens cap!

Black as a colour - nonsense. What we perceive as black is brought about by maximal absorption or minimal emission of visible light by a body.

Frankly it's all based on what a wobbly sphere of cells can and can't detect, so you could have something that pounds out UV, IR, microwaves and gamma radiation and still call it black.

He was probably misquoted. Or perhaps they need artificial star on very black background to get best contrast.

Good reading on subject: http://www.astrophoto.net/calibration.php

The article has a lot of dubious claims, but it boils down to "this material doesn't reflect visible light at all at any angle".

>Just covering with a lens cap would seem to be a simpler way of accomplishing that

I'm sure it's a bit more complicated than that.

>Really? I can't think of any better way of describing black.

Good for you...? You must not be a scientist.

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