---
title: 'You''ve Never Seen a Real Photo'
source: 'https://youtube.com/watch?v=-DyrBDsKA5s'
video_id: '-DyrBDsKA5s'
date: 2026-06-28
duration_sec: 0
---

# You've Never Seen a Real Photo

> Source: [You've Never Seen a Real Photo](https://youtube.com/watch?v=-DyrBDsKA5s)

## Summary

The video explores the 135-year-old Lippmann plate photography technique, which captures the full spectrum of light instead of faking colors like standard RGB photography. It explains how the plate achieves structural color via interference, similar to soap bubbles and chameleon skin, and highlights the plate's ability to produce spectrally accurate images.

### Key Points

- **Standard Photography Is a Scam** [0:34] — Standard photography uses only red, green, and blue to fool the eye, while Lippmann plates capture the actual wavelengths.
- **How Lippmann Plates Work** [10:10] — The plate works via interference of light reflected from a mercury layer, creating standing waves that expose silver halide crystals.
- **Color Shift from Moisture** [2:57] — The breathing demonstration shows the gel expanding and shifting the structural color, analogous to chameleon skin.
- **Structural Color Explained** [4:25] — Structural color comes from interference, not pigments, as seen in soap bubbles, DVDs, and chameleons.
- **Silver Mirrors as Diffraction Grating** [12:17] — The final developed plate contains silver mirrors spaced according to the original light's wavelength, forming a diffraction grating.

## Transcript

This video is sponsored by Incogn. I
made this rubber band that changes color
when you stretch it. It's cool, isn't
it? It starts off blue, then goes green,
and then red, and then when I let go, it
returns back to blue. And it's the same
mechanism that's used in this
135year-old photography technique that's
halfway between a hologram and a
photograph. It's the same chemistry as
black and white photography. But look,
when I change the viewing angle, it
bursts into color. And this isn't just
any color image. It's arguably the
truest color image you'll ever see. And
that's because standard color
photography is a lie. That's a bit
inflammatory, isn't it? Helps with the
views. All right. Here's why standard
color photography is a scam. So, when
you take a picture of something yellow,
let's say, then you've got yellow light
hitting the sensor of the camera. And
that light has a wavelength of about 580
nanome. But when you look at the
resulting image, you're not getting that
wavelength coming from the image.
Instead, you're getting some red
wavelengths and some green wavelengths
that your brain interprets as yellow.
And that's because we don't have
dedicated cone cells in our eyes for
yellow wavelengths of light. Whereas,
when I look at this image, all the
wavelengths of light that were hitting
the plate when the picture was taken are
now hitting my eyes as I look at it. And
that's because it's basically a hologram
except it's encoding color information
instead of depth information. For the
vast majority of people, you'd never be
able to tell, but we can use this
spectrum analyzer to see it. So look,
this is my phone screen through a
spectrum analyzer. And as I move around
the image, what you're seeing is just
three peaks changing in height. That's
red, green, and blue. And they match up
with the three types of cones in our
eyes. But when I point it at the Litman
plate, you can see this complex
distribution of wavelengths. And because
there are flowers in this image, we're
even getting a bit of ultraviolet there
as well. Actually, that's a good point.
Standard photography doesn't work for
other animals, like bees, for example,
because they have a different
distribution of cones in their eyes. And
actually, even for a tiny minority of
humans that have four different cone
cells and the neurological machinery to
use the extra one, the yellow in this
Litman plate will look like the yellow
they see in real life, whereas yellow in
standard photographs would look wrong.
So, how is it that this black and white
film can reproduce the full spectrum of
colors from the real world? Well,
they're called Litman plates, and they
were made for me by an amazing
photographer called John Hilty. I really
hope you'll check out his stuff. I'll
leave a link to it in the description.
And once I had them in my hands, I just
thought, well, I have to show this to
the world. So, here we are. We're going
to figure out together why color seems
to magically emerge from this plate.
Here's a clue to start with. Watch what
happens when I breathe on this plate.
See how the whole rainbow seems to shift
to the left? Why the heck does it do
that? Well, surprisingly enough, it's
for the same reason that chameleons
change color. Watch this.
Yeah, that didn't work. I don't know why
I thought that would work. Anyway, we'll
get back to chameleons later, I promise.
But let's use this rubber band of mine
first. We'll call it synthetic chameleon
skin because it too changes color for
the same reason that a Lipman plate
changes color when it's breathed on. So,
the way I made this rubber band is I
pulled the DVD apart and poured some
silicon on this exposed surface inside.
In other words, I used that surface as a
mold. The surface looks really flat, but
it's actually covered in tightly packed
grooves. So, now my rubber band also has
these tiny grooves in it. And it's these
tiny grooves that bring the colors out.
So, again, it's not color pigment like
the silicon doesn't have any color of
its own. It's transparent. Instead, the
color comes from the structure of the
surface. That's why it's called
structural color. And that means if you
can change the structure by stretching
it, for example, then you can change the
color. How cool is that? How a Lithuan
play ends up with structural color is
amazing. But first, what is structural
color? Well, my favorite example is
bubbles. Why do you get rainbows in
bubbles? Well, let's zoom right in on
the bubble film and see what happens
when light shines on it. Some light gets
reflected and some light gets
transmitted from that top surface. Then
some gets reflected and some gets
transmitted from that bottom surface.
And then some gets reflected and some
gets transmitted from the top surface.
Again, suppose this is red laser light
we're shining here. And this is the
wavelength. Now, it just so happens that
this distance here is exactly one full
wavelength of the red light. So you can
see that the peaks and the troughs line
up perfectly. So when you add them
together, you get an even bigger wave.
That's called constructive interference.
But what if we switch to a blue laser?
Well, now this distance is one full
wavelength and a half. So now the peaks
of this wave line up with the troughs of
this wave and vice versa. So when you
add them together, they exactly cancel
out and you get no light coming out.
That's called destructive interference.
Now, for in between wavelengths, you
wouldn't get perfectly constructive
interference or perfectly destructive
interference. So, you'd get a brightness
in between for intermediate wavelengths.
Except what's actually happening here is
the light is bouncing up and down inside
this soap film multiple times. What does
that mean for those in between
wavelengths? Well, when you add up loads
of offset waves like this, it ends up
looking like complete destructive
interference anyway. In other words,
when you have lots of reflections, the
interference becomes really selective
and it gets tighter the more reflections
there are. So, you end up seeing only
that one perfect wavelength of red light
that exactly matches and a little bit
either side. And the reason you see
rainbows is because the angle that the
light enters the film at changes this
length. So here red light is reflected
and here blue light is reflected and you
get the full spectrum between these two
points. So that also explains why DVDs
have rainbows in them except that
instead of the light bouncing up and
down inside a thin film of soapy water,
you've got light that's reflecting off
closely packed ridges. So actually the
same thing is true for my rubber band.
You see different colors at different
angles. The difference is that I can
shift the rainbow by stretching it. And
that makes sense because when it's
stretched those ridges become more
spread out and so the wavelengths that
constructively interfere become longer.
And the same thing happens when a
chameleon changes color. So a chameleon
has these special cells called
iridaphors that are packed full of these
tiny regularly spaced crystals of
guanine. When the crystals are tightly
packed, they cause constructive
interference for blue light and
destructive interference for all the
other wavelengths. But a chameleon is
able to engorg these cells by changing
the osmotic pressure. When the cells
expand, the crystals move further apart
from each other. This causes the
crystals of guanine to spread out so
that they constructively interfere
longer wavelengths of light. That's not
the whole story though. Like chameleons
also have a pigment layer. So the final
color that you see is a mixture of
structural color that the chameleon can
tune and this pigment color. Real
chameleon skin differs from my synthetic
chameleon skin in a couple of ways. The
first is that with my synthetic
chameleon skin, the interference is
happening because of surface ridges.
Whereas with real chameleon skin, the
diffraction is happening through deeper
and deeper layers into the skin. The
other difference is that real chameleon
skin isn't iridescent, which is actually
really impressive. Like, if there's
diffraction going on, why don't I see
the color change when the viewing angle
changes like it does with this mother of
pearl or this peacock feather? It's
actually a bit easier to see how moro
butterflies do it. That incredible blue
is also structural color. And just like
the chameleon, it looks blue from all
angles. To see why, you have to look
under an electron microscope. This is a
cutaway through the wing. Here's a
diagram of it for simplicity. So, the
interference comes from these ridges
here. So, if light comes directly down,
it interferes with this stack of
branches, and they're spaced for blue
light. Now, if all the branches from the
neighboring trees lined up like this,
we'd get iridescent. Because look, when
light comes in at an angle, it can
bounce off this top branch, then the
second from top branch on this
neighboring tree and so on. And each gap
is the same distance. So you've got
constructive interference for say red
when viewed at this angle. But cleverly,
the moro butterfly has all these trees
offset randomly at different heights
from each other. So when light comes in
at an angle, it doesn't see regularly
spaced reflectors. it sees a random
mess, so constructive interference is
impossible. So, you only get reflected
light when it's coming straight down,
and that's always blue. Chameleons do a
similar thing with those guanine
crystals, but it's not as easy to
visualize. But anyway, we finally come
full circle back to the Litman plate.
So, when I breathed on the back of this
Lipman plate, the gel on the back
absorbed some of the moisture from my
breath and expanded. And so just like
the crystals inside the chameleon skin,
the structures inside this plate
expanded and separated when engorged
with water. And that separation causes
the color to shift. But what are these
structures inside the Litman plates? And
how did they get there? To figure it
out, let's look at how one of these
pictures is taken. First, take a sheet
of glass and coat it in a photographic
emulsion. This emulsion is made of
gelatin with lots of teeny tiny crystals
embedded in it. These are tiny grains of
silver haloid, meaning a latis of silver
and something like broomemide. You then
put the plate face down in a bath of
mercury. I don't have any mercury, so
you'll have to use your imagination.
Now, let's see what happens when the
plate is put in a camera and exposed to
light. In particular, we'll zoom right
in and see what happens when yellow
light hits this little section of the
plate. First, it passes through the
emulsion from the front and then it gets
reflected off the mercury bath and then
it passes back through the emulsion from
the back. And crucially, the reflected
light interferes with the incoming light
and that creates a standing wave. You
know, standing waves, right? The
important thing is you've got light
energy here at the antinodeses and no
light energy here at the nodes. And so
these crystals here at the antinodeses
start to absorb photons. And eventually
as a result, some of the atoms in those
crystals break away from the halite
atoms and form metallic silver flakes.
Just over here, the plate is maybe being
exposed to blue light instead. Blue
light has a shorter wavelength. So these
bands of exposed crystals are closer
together. In other words, the color of
the light is encoded into the spacing
between these bands. After the image is
exposed, the plate is developed. And
this bit is really clever. So you've got
this emulsion with silver haly crystals
in it. And some of these crystals have
little silver flakes in them from the
exposure. And these silver flakes act
like a catalyst during development. so
that any crystal that contains even a
tiny amount of metallic silver becomes
entirely metallic silver by the end.
There's a final step that flushes away
all the silver haly that didn't get
converted into metallic silver and what
you're left with is lots of tiny silver
mirrors embedded in gelatin. Then to
view the plate, you just shine white
light onto it. And every time the light
hits one of the mirrors, some gets
reflected and some gets transmitted down
to the next mirror and so on. And just
like with the soap bubble and the
chameleon and the butterfly, the
resulting interference produces a
specific color that depends on the
spacing of the mirrors. In other words,
the Litman plate contains a defraction
grating that encodes all of the spectral
information from the original scene. So
why does it only work when it's
illuminated from certain angles? Well,
with normal pigments, you have light
scattering. So white light can hit the
pigment from any direction. Some of it
gets absorbed, some of it gets
scattered, and some of that scattered
light reaches your eyes. But when light
scatters off a Litman plate, you don't
get interference. So you see it as black
and white. It's only when the light
reflects off the surface that you see
the color. Which is why when I shift the
focus of my camera lens here, you can
see that the light source is reflected
there in the plate. You know, Litman
plates have their drawbacks. Reprints
are basically impossible. Exposure times
run to minutes. the restricted viewing
angle is less than ideal and they can
get a bit washed out if you don't get
the process exactly right which is
probably why pigment-based RGB
photography eventually came to dominate.
So, Lipman plates might feel like a
historical culde-sac, but it turns out
that holograms like this one that can be
viewed with reflected white light are a
direct descendant of Litman plates. So,
you know, thank you, Gabriel Litman. You
deserved that Nobel Prize. Right,
massive tangent. I love scams. What I
mean is, well, I'm interested in
everything, including scams. So, when I
get a scam phone call, I try and keep
them on the phone as long as possible
because I'm interested to know like what
are their tactics and stuff like that. I
don't particularly recommend it cuz you
could end up giving away something
unintentionally. But let's have a look
at an example. This is a phone call from
my bank. So, you're
>> Yes, you
wigs. I thought you'd know my address.
>> No, I can send you over a text message
now.
Yeah. Okay. It's interesting to see how
they socially engineer their way around
various safety features built into the
banking app. For example, there's a big
banner in the app that basically says
we're not calling you. So like if the
bank isn't calling me, who the hell are
you?
>> Yeah, it's just Okay, I'm just telling
you now. It says here, you've never
spoke we've never spoken to you on the
phone.
>> Yeah, that's correct, sir. That's what
we've got added onto your account cuz if
somebody else has logged in, they can
see when's the last time you've been on
the call with us here, sir. Maybe you're
seeing some red flags here. But the
thing that gave it away perhaps more
than anything was just how frustrated he
was getting with me. Anyway, carry on.
So, what what what do you need me to do?
>> Are you recording the call, you
>> I'm not recording it. Are you genuinely
>> Are you sure you're not recording?
>> This guy that wasn't very convincing. I
just don't think my bank would speak to
me like that. It became clear from the
call that they had my bank details,
which was worrying. And I actually
figured out how they must have got it
because while he was trying to persuade
me of his legitimacy, he read out my
email address, but the email address was
wrong. It's not the one from the
account. It's a random one that I hardly
ever use. But I remember I did use it
recently for a specific transaction on a
camping website. So my guess is that the
caller must have used something like SQL
injection on that camping website to get
my car details. But anyway, every time
you put your details into an online
form, you're hoping that the company
behind it has good security. Obviously,
that's not always the case. So, it's a
good idea in general to try and minimize
how many companies have our data. The
good news is that our data has been
consolidated to a large extent by these
middleman companies. So, if you can get
your data off their databases, it can't
trickle down to all the others. Not only
would you be less vulnerable to data
breaches, you'd also get fewer spam
calls. The bad news is there are
hundreds of these middleman companies
called data brokers. And they all have
different procedures for requesting data
removal. Honestly, if one person could
just sit down and do all the hard work
of figuring out how to interact with all
of these different companies to remove
their data, well, I'd happily pay them a
little bit of money to do the same thing
for my data since they've already done
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