In a previous video I did on the Connectix Quickcam, the first ever webcam for personal
computers, I showed a technique for capturing color stills from an otherwise black and white
camera.
A lot of people were totally blown away by this sorcery and wanted more information about
it.
So, I had promised a more in-depth explanation of this process in a later video, and well,
here we are.
And, this process is actually not new.
In fact, it was first proposed by James Clerk Maxwell as early as 1855.
However, it didn’t see a lot of practical use until the early 1900s.
Russian Chemist Sergey Prokudin-Gorsky helped to popularize the idea around 1906.
He used a regular black and white camera of the era, and placed a color filter in front
of the lens.
In this case, a red color filter will block all light that is not red.
If you were to look through the color filter the parrot would look sort of like this.
Of course, some colors like white, purple, and brown also contain red light.
But colors like blue and green would appear as black.
Of course, the film in the camera is still black and white so it would actually record
the image like this.
So, if you consider doing this 3 times with all 3 primary colors, the parrot would look
more like this.
And of course, on the black and white film it would look like this.
So even though the film itself is not in color, you still have the 3 representations necessary
to reconstruct the color image.
But how did Sergey display the photos?
Well, he created a special slide projector that projected three slides at the same time,
each one using a different color of light.
And so he could place the 3 black and white photos in the projector, and the red, green,
and blue light would reconstruct the color image on the projector screen.
And using this method, he actually took some pretty amazing photographs.
It’s hard to believe that these photos are over 110 years old.
And, of course, this concept is not exactly considered outdated either, because most of
your really high end professional cameras still use the same concept.
They have some cleverly shaped prisms, so that when the light comes through the lens,
it is broken into red, green, and blue light like this.
And then there are 3 separate image sensors to pick up the light, and each of these sensors
is in fact a black and white, or monochrome sensor.
So, I wanted to experiment with this concept a little more, but I wanted a camera with
at least a little bit better quality.
So, I picked up this old black and white security camera, which outputs a composite video signal.
So I can use my laptop with a video capture device to grab the images.
This camera requires 24 Volts Ac, so I’ll need to wire up this A/C adapter to power
it.
The camera has essentially 3 settings, you have aperture control here, then zoom here
in the middle, and focus here at the tip.
So, this is what the camera sees.
And I’ll need something to take a picture of.
I’ll use this little Pacman figure.
Actually, I’ll give him the company of Ms. Pacman as well.
And just for a little extra color, I’ll add in Mr. Meeseeks.
So, I’ll just hold the color filters one at a time in front of the camera.
When I use the red color filter you can immediately see that Mr. Meeseeks turned dark because
he’s mostly blue.
OK, so how do we take these 3 grayscale images and turn them into a single color photo?
Well, there are many programs out there which can do it.
I’ll demonstrate this using Gimp.
So here are the 3 individual grayscale photos and I’ll just drag them into Gimp.
And there we go.
So, let me re-arrange these a bit.
So yeah, here’s the red, then the green, and the blue.
And you should be able to tell some difference in brightness, for example, on PacMan here,
that he appears darker in the blue image.
Anyway, so how you combine these is you go to colors, then components, then compose.
Then this little dialog pops up.
Obviously we want to use the RGB method.
Then I just need to select the correct photo to use for each channel here.
And then, viola!
There’s my color photo.
It probably wouldn’t hurt to increase the saturation some.
I think the color filters I have are not 100% pure, so they allow some light to come in
from other colors, which means the separation isn’t perfect, but I would imagine increasing
the saturation like this should more or less compensate.
Well, let’s try another one.
This is some fake decorative flowers.
They look pretty plain here in black and white.
But, I was able to get this photo using the filters.
And, how about these little mini arcades.
I need to tighten up the focus.
Ok, let’s see what we can get from this.
There we go!
Now, let’s try this unsolved Rubik’s cube.
In fact, I’ll mix it up a little more.
In fact, I’ll also add in the Rubiks Snake.
I’m going to straighten that up just a bit.
And there we go!
This came out beautiful!
OK, so I wanted to try this on a human subject.
My daughter’s friend Jordyn volunteered to be my guinea pig, or glamour model, however
you want to look at it.
The trick is, she’ll have to stay extremely still while I take the 3 separate photos.
And here are the 3 photos.
However, combining them together didn’t work out that great, as you can see a lot
of color fringing down the left and right of her arms and face.
This is because she moved ever so slightly during the take.
Also this is a bit overexposed.
So I tried closing the aperture some to darken the image.
This camera doesn’t have very good dynamic range.
Anyway, that resulted in more facial features, but added some graininess to it.
And despite several attempts, we were never able to get a perfectly clear shot due to
Jordyn having moved at least some between captures.
I decided to try this outdoors, which was actually quite challenging because I needed
to carry a laptop with me, along with a portable power unit so I could plug in the camera to
get the 24 volts AC power.
We went to the local town center here in Kennedale and I setup the laptop and camera.
I had both of the girls pose for the camera.
But one of the biggest problems was getting the focus right because the sun was washing
out the screen on my laptop and I just couldn’t see any detail.
The interesting thing is, the final photos seem to have very little color to them.
And I was quite perplexed by this.
And the color they do have seems to be mostly from sun glare on the different color filters,
which I couldn't see while taking the photos due to the laptop screen.
Interestingly enough, this clock tower probably came out better than any of them, despite
the moving clouds and the wind blowing the plants and trees.
And here’s the final color image from this.
However, I was able to determine at least one of the problems I was having.
You see, this camera picks up a good deal of both ultraviolet and infrared light, along
with the visible spectrum.
And that’s not a flaw, it was actually designed to do that because it’s a security camera
and that way it would have better light pickup under low light conditions.
So I took my little filters and tested them with this UV flashlight.
As you can see the camera picks up the UV quite well, but you can see the filter blocks
most of it.
So that’s good.
But what about infrared?
I tried this remote control and as you can see the filter does not block any of it.
Of course, the filter probably wasn’t designed with that in mind since most cameras would
probably have some kind of infrared blocking device already in the camera.
It just so happens this one does not.
So, I think if I were to figure out some way to block the infrared light, either inside
this camera or outside the lens, I think I could make these photos look a lot better.
You see, the reason that this picture has so little color is that there is a lot of
infrared light outdoors and all of that light got through all 3 color filters, where as
the indoor photos came out better because I have LED lighting in the house, which doesn’t
emit much infrared light in the first place.
Anyway, it gives me a lot of respect for Sergei Gorskii because he was able to take these
magnificent photos back in 1906 to 1912 using this same technique, long before color photography
was really a thing.
And what’s more amazing is that his subjects were able to remain so completely still.
Of course, not all of them because if you look at this photo, you’ll notice this one
girl was apparently not able to remain completely still because you can see the color fringing
around her.
So, I propose a new photography challenge.
I mean, why challenge yourself with film or instamatic, or gameboy cameras when you can
challenge yourself with a black and white security camera.
There you go, so once you take some masterpieces with one of these bad boys, send me the result
and let me see what you did.
Otherwise, until then, thanks for watching.