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    Some background: https://www.theguardian.com/education/2026/may/12/thousands-of-university-of-nottingham-staff-told-they-are-at-risk-of-redundancy Not only does Nottingham University have a good academic reputation, the city of Nottingham has a great…

A new shade of blue

Brian Leiter

MOVING TO FRONT FROM JANUARY 28:  UPDATED

Who knew it was possible?

(Thanks to Phil Gasper for the pointer.)

UPDATE:  Philosopher Mark Eli Kalderson (UCL) writes:

Just a quick comment. The discovery of a new blue pigment is not the discovery of a new shade of blue. The former is some material stuff, the latter is a property. This distinction was drawn by Aristotle and the Peripatetic author of De Coloribus (both claim that color mixture is not to be understood on the model of mixing pigments.) So the relevant conceptual distinction has been in place for over two millennia. It remains newsworthy that the first new blue pigment has been discovered in centuries. But a new shade of blue? Fake News!

ANOTHER:  Philosopher Mohan Matthen (Toronto) writes:

Mark Kalderon is clearly correct to say that there is a distinction between shades of blue and blue pigments. He’s probably also right to say that YInMN blue is not a new shade. 

But (and no doubt this is not what Mark was suggesting) it’s not impossible to discover new shades. Vantablack is a shade of black that had never been seen before. Presumably, it existed in the Platonic world of possibles, but being absorbent beyond any pigment or natural substance ever seen before, it was indeed a new shade, at least as far as colours realized on this planet go. It’s possible that YInMn blue is new in this sense. It’s supposed to be extremely brilliant.

I'll open this for further comments from philosophers and others knowledgeable about the metaphysics and science of color.  Signed comments (full name, valid e-mail, which will not appear) will be strongly preferred.

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7 responses to “A new shade of blue”

  1. Stephen Rive

    Different surfaces absorb some wavelengths of light and reflect others, and that's what registers in our brains as differences in colour. Chlorophyll absorbs all wavelengths except what we see as green, so leaves are green. So am I over-simplifying to say here that what we have is a new surface that reflects and absorbs wavelengths of light in a way that nothing else did before? That this surface "selects" a wavelength for reflection, while absorbing all others, that is both visible to our eyes and also not "seen" before, because hitherto no natural surface had this property?

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  2. Curtis Franks

    I once (20 years ago?) attended a lecture of Donald Hoffman (UCI cognitive scientist whose evolutionary argument against veradical perception was recently batted around in comments on this 'blog) at which he demonstrated how to construct new shades of color more or less at will by triggering the active part of our neuronal color perception faculty in deliberately unusual ways. Most memorably, to me, he "showed" us a shade of rich, brilliant, shimmery yellow that we all experienced as, and judged to be, much darker than a swath of pitch black that he showed us simultaneously.

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  3. Mohan Matthen

    Responding to Curtis Franks: The so-called impossible colours are good candidates for novel shades. In the early 80s, Piantinida and Crane famously produced an experience of a reddish green by stabilizing a red-green boundary on the retina (using an eye-tracker)—reddish-green is supposed to be an impossible shade. It sounds as if the Hoffman shade is something of the same kind, where the brain is induced to produce a yellow that is darker than black (which should be impossible). However, YInMn blue is a different kind of case than either of these because it is a pigment . . . a substance with a stable colour. (Same for Vantablack.) No fooling with the brain needed.

    Responding to Stephen Rive: any colour can be produced by mixing lights of different wavelengths, or by mixing different pigments. And this can be done in different ways . . . different mixtures look colour-equivalent. Because of this, we moderns have seen just about every possible shade, because our colour monitors can mix up the RGB appropriately. (This was not always true: a couple of thousand years ago, I figure, nobody had seen a truly saturated red.) What is impossible is getting certain colours to exceed certain levels of brightness or darkness relative to other colours seen simultaneously. It sounds as if YInMn blue is perceptibly novel because it is "unnaturally" brilliant. I wish I could see it! (Photographic reproductions wouldn't do it justice. You can't take a photograph of Vantablack either, because the dyes on the photographic surface don't absorb enough light.)

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  4. Allen Hazen

    Old discovery (I learned about it when I was a student in the beginning of the 1970s): it is possible to experience a color ("shade") that can't physically exist. Method: stare at bright green for a while, so as to experience a red afterimage. Then look "through" it at a bright red physical stimulus. Apparently subjects who have done this report that the color they experience is a VERY intense red: a more saturated red than can be experienced by looking, without the distortion of afterimages, at any red physical stimulus. (When I taught Descartes's "Meditations" to undergraduates, I used to bring this up in connection with the passage about how a painting, of even the most bizarre fantasy creature, is at least painted in "true colours": is this what a "false" color would be?) Not as dramatic, maybe, as the example Curtis Franks tells about (and I've never "seen" it myself), but evidence that the possibility of "perceived" though physically impossible colours was known before the Piantanida (sp?) and Crane experiment Mohan Matthen reports. … … One of the benefits of studying philosophy, it seems to me, is shaking (or at least making us more aware of) our own preconceptions: I think a valuable undergraduate course would start by getting the students to feel the intuitive plausibility of various theses about sensa and qualia … and then introducing both conceptual and EMPIRICAL (like the examples mentioned in this spring) reasons for finding them problematic!

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  5. Jonathan Birch

    Isn't Vantablack the colour of space?

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  6. Mohan Matthen

    Not if there is always some light that reaches the eye from every direction in space. That's the thing about Vantablack: it's so non-reflective, it is said to look like a hole. (Put that way, I guess that deep, narrow holes would be Vantablack, except that they are so small that they are smaller than minimum visibilia.)

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  7. Michael B

    I have seen, and handled, Vantablack before. I was at a science festival for kids and the makers of Vantablack were there. [Incidentally, I was there as I had been hired to wander around in a toga pretending to be Pythagoras. Nobody got my joke about philosophy being a series of footnotes to me. I was disappointed. The kids were just embarrassed.]

    I don't really know how to describe Vantablack in terms of what I saw. It is just really, well, black! Like when you buy a new ink pen and far too much black ink comes out at once. A deep black. And the surface looked smooth. Almost glossy (which can't be right – maybe I'm remembering it incorrectly). Maybe it just looks so smooth as you can't tell otherwise just by looking. The Wikipedia photos do a good job of showing this.

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