[HN Gopher] A man preserving endangered colours
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A man preserving endangered colours
Author : throw0101a
Score : 51 points
Date : 2021-08-25 10:42 UTC (2 days ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| RattleyCooper wrote:
| Whether natural dyes look different or not is unknown to me,
| however I bet $100 that dude couldn't tell the difference if you
| mixed in a bunch of synthetically dyed material with the
| naturally dyed stuff. Put the natural and synthetic dyes in a
| lineup together and I bet there is no way for him to reliably
| tell them apart.
| drdeca wrote:
| Is one allowed to vary the lighting conditions while examining
| them?
|
| If in one collection, one has different mixes of 4 fixed dyes
| or pigments which each respond to the light in a particular
| way, then, the way the result responds to different light
| sources should be in a particular 4d space, while more
| generally pigments could have the lighting->appearance function
| be a point in a larger space which that 4D space is a subset
| of, right?
|
| I don't particularly know what I'm talking about in this
| comment, but it seems to me like it should be right..
|
| Though, even if what I said is right, there's still the
| question of whether _a person_ could reasonably learn to
| recognize whether such a response function ("response function"
| is not some technical term that I know. If it is a technical
| term, it is likely I'm using it wrong. I'm just using it as a
| description of the function from lighting to apparent color.)
| is from such a 4D subspace or not.
|
| Based on a video I saw, I suspect that in some cases, yes, but
| in general idk. How often would the function be very close to
| something that is in the 4d subspace but isn't quite?
|
| I imagine a machine could do it easily.
|
| Assuming you have a cheap way of producing light of a variable
| wavelength? Do we have such a thing? I think electron vibrating
| lasers (Idr the proper name for them) have a tunable
| wavelength, but I imagine those are expensive, and also
| probably something that isn't a laser would be preferable.
| dm319 wrote:
| As we have three cones used to observe tone and colour, the
| colour/tone of something occupies a 3D space.
|
| However, as you say, a pigment colour has high dimensional
| properties - the spectral response. As others have mentioned
| this determines how it impacts on the observed/perceived
| colour, depending in the spectral response of the light it
| reflects.
| dillondoyle wrote:
| Might it be like diamonds where the imperfections give it away?
| Maybe we'll see similar marketing that natural is more unique
| than 'artificial.' I could see that having $elling value in
| fashion, one of my friends does natural dying in Mexico and the
| selling point is uniqueness.
| swayvil wrote:
| Computer colors. On the screen. Are more like references to color
| than actual color. A minimal kind of "red symbol", referring to a
| memory of something red.
|
| I've come to realize this recently. I've been doing a lot of
| flower gardening.
|
| Digital music is similar.
|
| 1% substance and 99% mindgame
| injidup wrote:
| """ When compared with the synthetic dyes that are used today in
| essentially all our clothes and textiles, nature's version is
| almost always inexplicably better. It's the visual equivalent of
| a peach ripened by the tree, or a tomato baked in sunshine. Some
| lost part of you recognises that this is how it's supposed to be.
| Natural dyes are no different. """
|
| Very poetic. But is there any truth to this or is it just poor
| journalism?
| malfist wrote:
| Just your general "technology bad, hard way better" luddite
| ramblings. Just because something takes more work to do it that
| way, doesn't mean it's better.
| ink404 wrote:
| This is clearly something you'd need to see in person to
| understand before making a statement like that.
| deertick1 wrote:
| Totally disagree. 1) im 99% sure that some colors we cannot
| or do not precisely recreate using non natural dyes. Just
| thinjing about the complexity of organic material: that is
| bound to produce subtle textures and such that are not easily
| mimicked.
|
| 2) there is a spiritually satisfying element to recreating
| something in the original or natural way when a more complex
| way may be easier
|
| 3) it is important to preserve the heritage of human
| innovation. These techniques and recipes ought to be
| preserved for historical and sociological reasons, as well as
| in the event that shit goes to pot one day, we may still have
| some people that know how to make dyes from scratch.
| Aardwolf wrote:
| I just saw a rose garden with differently colored roses, and
| some made me think: this is a color a computer screen can't
| show
| Igelau wrote:
| I've run into this before in watercolor. RGB seems like
| such a massive color space until suddenly it isn't.
| evanb wrote:
| Relevant: "I can't show you how pink this pink is." by Tom
| Scott https://www.youtube.com/watch?v=_NzVmtbPOrM
|
| Also relevant, his piece on "The Library of Rare Colors"
| https://www.youtube.com/watch?v=rApTzWboLrA&t=6s
| km3r wrote:
| Many artificial dyes use CYMK dye colors to build up to the
| final color when they are mixed by our eyes. Natural dyes will
| often truly be that color or a unique combination of non-CYMK
| colors. The result of this is non pure white light will reflect
| off the surface of the dyed object in different ways. It's a
| similar reason many LED lights look different than natural
| sunlight, with the LED lights using a combination of RGB.
| hammock wrote:
| Another aspect that is missing from consideration is the
| element of time.
|
| Synthetic and natural dye will degrade or "patina" in
| different ways, over time and over the course of exposure to
| weathering, UV light, etc.
|
| In many cases the synthetic dye does not degrade at all,
| which for many use cases can be undesirable.
| canadianfella wrote:
| When would it be undesirable?
| OscarCunningham wrote:
| The Color Rendering Index [0] measures how well a light
| source shows the colours of various objects faithfully
| compared to natural light.
|
| Perhaps we also need a dual index that measures how well a
| pigment retains the same appearance under various light
| sources.
|
| [0] https://en.m.wikipedia.org/wiki/Color_rendering_index
| marto1 wrote:
| Could that mean that animals with different sight systems see
| gibberish when presented with something artificially dyed ?
|
| My thinking is this could affect visual cues for e.g.
| training.
| BurningFrog wrote:
| Absolutely.
|
| Human sight reduces all visible light down to the three
| red/green/blue buckets. Other species will have different
| buckets, and can easily see colors we perceive as identical
| as completely different.
|
| I believe we have better color vision that most animals
| though, so the opposite is usually the case.
| nick__m wrote:
| It's a lot more complicated than RGB buckets, there is a
| serie of preprocessing cells
| https://en.wikipedia.org/wiki/Retinal_ganglion_cell
| before the image "signal" is further processed by the
| visual cortex.
|
| Another species could have the exact same "buckets"
| configuration and perceive color differently if the
| ganglionic layer is connected differently to those
| buckets.
| wahern wrote:
| Some humans enjoy tetrachromacy. There's an article
| floating around where one such woman mentions that in her
| world she sees mismatched colors everywhere; colors that
| to everybody else look identical (e.g. on a shirt and
| pants, or two walls) but which to her look different,
| sometimes significantly. IIRC, the fourth spectrum peak
| isn't that far away from one of the others, so I assume
| this effect is probably exaggerated by artificial dyes
| that reflect in relatively narrow bands.
|
| EDIT: Here's the reported anecdote I was remembering:
|
| > "I have always had polite disagreements with people
| about shades of colours," she says. When clothes shopping
| for instance, she often finds that apparently matching
| tops and skirts seem to be a different shade to her,
| clashing horribly--even though no one else seems to
| notice it. Her sensitivity can sometimes be baffling to
| those around: when helping to restore a house, she once
| rejected 32 paint samples before settling on the right
| shade. "The beiges were too yellow and not blue enough,
| not cool enough; some of the almonds were too orangey,"
| she says--distinctions that were much to the confusion of
| her building contractor.
|
| https://www.bbc.com/future/article/20140905-the-women-
| with-s...
| cpeterso wrote:
| Humans see "gibberish" colors, too! For example, the color
| magenta doesn't have a wavelength on the ROYGBIV spectrum
| and is instead an artifact of your eye's rods and cones:
|
| https://www.youtube.com/watch?v=8FSpCAs5KZg
| hammock wrote:
| Depends on how their brains process the colors. Basically
| what parent commenter is saying, is the color systems we
| use do not cover the entire gamut of visible light.
|
| Visualization of this: https://imgr.search.brave.com/OsaL9H
| ps1NYNjbK4zhGnStZmlMNT3t...
| BurningFrog wrote:
| Does `truly be that color ` mean the dye only reflects the
| wavelengths around the individual frequency?
|
| I can see how that would actually make it look
| better/different in non full spectrum light!
|
| But I don't get how pre tech dye experts would pick such
| colors?
| Bokanovsky wrote:
| The non-CYMK colours also reminds me of flowers. If you look
| at photos of flowers, or just look normally, you'll see
| solid/uniform colour.
|
| But if you look at infrared photos of flowers or "how bees
| see them", they show the same flowers with landing strips for
| the bees.
| IncRnd wrote:
| According to my eyes, it is true. The colors he works with are
| beautiful and visually different from synthetic dyes.
| canadianfella wrote:
| It's bullshit.
| sp332 wrote:
| Synthetic and natural dyes each have their advantages, which is
| why they are still used in various applications. But which kind
| you like better is obviously a judgement call.
| mc32 wrote:
| I think it's more poetic. Yes, the results may be different and
| they have values that synthetics don't possess, more
| variability for example or less colorfastness, but to say that
| overall they are inexplicably better, is overselling it.
|
| Sure, I like indigo, woad and maybe carrots or beets for Easter
| eggs but that doesn't mean they are better. There may be
| preferences, yes. Better? That depends on use.
| throw0101a wrote:
| As a sibling comment noted, there are only a limited number of
| artificial dyes in existence, so what you see in the natural
| world may have more colours.
|
| See for example the splash that a 'new blue' made recently:
|
| * "The first blue pigment discovered in 200 years is now
| commercially available",
| https://news.ycombinator.com/item?id=25807199
|
| * "YInMn, the First New Blue Pigment in Two Centuries",
| https://news.ycombinator.com/item?id=25963292
| crazygringo wrote:
| That's not really relevant here though.
|
| The set of synthetic dyes we have does a pretty fantastic job
| at covering all the colors seen in the natural world, plus a
| whole lot more. We go _way beyond_ the natural world, in
| fact, when you look at the bright /fluorescent colors you see
| in an athletic clothing store, as I mentioned in another
| comment.
|
| What makes that 'new blue' you refer to special has nothing
| to do with how we perceive it directly -- it's trivial to
| recreate that hue. It's useful for the very specific use case
| of _mixing colors while oil painting_. It 's for artists
| trying to blend colors.
| crazygringo wrote:
| Short answer: it's poor journalism.
|
| Long answer: there are mainly three factors that contribute to
| inaccurate color reproduction.
|
| The first is limited color gamut. That's not really a factor in
| dying fibers though -- we have plenty of synthetic dyes for
| things like bright orange, fluorescent green, etc. Just visit
| any athletic clothing store. And while yes nature has all sorts
| of shiny bright iridescence caused by diffraction etc., those
| properties are destroyed as soon as the material is smushed.
| You can't turn gorgeous insect wings into dye.
|
| The second is that while our eyes perceive only RGB in response
| to a wide spectrum, there are an infinite number of spectral
| patterns that we ultimately perceive as e.g. a certain orange.
| An orange dye from one source (natural or synthetic) will have
| a different source spectrum from pretty much any other orange
| dye (natural or synthetic). BUT it's pretty easy to match the
| color we perceive perfectly for a single lighting condition,
| e.g. sunlight. But this brings us to:
|
| The third factor, which is the spectrum of _lighting_. The
| spectra of sunlight, of fluorescent light, of LED light, is all
| different. The color we perceive is essentially the spectrum of
| the light source _multiplied_ by the spectrum of the dye.
| Therefore when we change the lighting spectrum, this _can_
| change the ultimate RGB color we perceive -- so that two orange
| dyes that appeared literally identical in sunlight now appear
| subtly different under a fluorescent light.
|
| So it is true that different dyes behave slightly differently
| under different lighting conditions. But there's no better or
| worse here, and there's _absolutely_ no "peach ripened by a
| tree" or "how it's supposed to be". That's complete and utter
| nonsense.
|
| The solution for good color matching isn't dyes from natural
| sources -- it's balanced, full-spectrum white lighting.
| hammock wrote:
| >And while yes nature has all sorts of shiny bright
| iridescence caused by diffraction etc., those properties are
| destroyed as soon as the material is smushed. You can't turn
| gorgeous insect wings into dye.
|
| Seems like a great technological opportunity for someone to
| figure out.
|
| Recently I advised someone not to buy granite countertops
| sight unseen, since the way they look in person is so
| different from the way they look in a photo - a photo
| completely misses the reflections, iridescence and other
| three-dimensional aspects of the actual product.
| crazygringo wrote:
| Oh yeah. Properties like reflectivity, translucence,
| internal reflection, and all that jazz play a big part in
| the final colors our eyes perceive as well.
|
| I didn't mention them since they have nothing to do with
| synthetic vs natural dyes though -- they're properties of
| whatever materials the dyes become part of.
|
| That's actually a significant part of why "accurately"
| photographing clothing for online shopping is so hard.
| Getting an accurate hue is usually _fairly_ easy with good
| lighting and proper white balance, and gray cards let you
| calibrate brightness. But the reflective properties of
| fibers mean that e.g. a shirt can look significantly
| different depending on what angle the light sources are at.
| hammock wrote:
| >I didn't mention them since they have nothing to do with
| synthetic vs natural dyes though -- they're properties of
| whatever materials the dyes become part of.
|
| I guess that is what I'm getting at, that today's
| conception of what a "dye" is, is that it is a substance
| which is added to a material not changing the reflective,
| translucent etc properties of that material (which is
| itself probably a simplification - I can't imagine dying
| a fabric doesn't change these at least a little bit).
|
| What I'm suggesting as an advancement is perhaps not
| called a "dye", but nevertheless would be a new way to
| not only change the color of the target object, but also
| the translucence, iridescence, reflectivity, etc.
|
| I know there is already stuff in this area - there was
| some laptop case I saw recently that had some kind of
| micro-texture on it (the opposite of a polish, I guess)
| in order to make the black color of it more matte (if I
| recall correctly). Likewise, anti-reflective coatings and
| privacy screens seem like a ubiquitous, primitive example
| of what I'm talking about. I'm sure there are others.
| colechristensen wrote:
| A lot of it is poetry, but there is a grain of truth to it.
| There are only a handful of artificial dyes and they'll usually
| be engineered to make up a colorspace which is always smaller
| than what your eye can perceive.
|
| For a more concrete example, no matter how nice your camera and
| printer are, the colors which can be reproduced are currently
| always restricted compared to the source material (reality),
| and not just in a matter of there being some small error, there
| are colors your eyes can see in nature which can't be printed
| with state of the art tech.
|
| Especially with textiles, the colorspaces available with normal
| technology are quite a bit smaller than in nature.
|
| Whether "natural" or "synthetic" (the distinction can be a bit
| silly) a substance will react to light in its own unique way.
| The number of different substances with different responses is
| obviously very large in nature, technology tries to recreate a
| full spectrum of color with only a few substances in
| combination, the result is naturally not as rich.
| throw0101a wrote:
| > [...] _there are colors your eyes can see in nature which
| can 't be printed with state of the art tech._
|
| As an example see sRGB, Adobe RGB, ProtoPhoto RGB, Rec.
| 2020/2100, _etc_ :
|
| * https://en.wikipedia.org/wiki/Color_space
|
| * https://en.wikipedia.org/wiki/Rec._2020
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