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How does the sensor work for capturing light for that long? Wouldn't it produce a solid white image after a single day? Is there any difference between taking a

How does the sensor work for capturing light for that long? Wouldn't it produce a solid white image after a single day? Is there any difference between taking a 1000 year exposure and taking a photo every day for 1000 years and laying them ontop of eachother?

MadnessASAP 3y ago
It's a pinhole camera, a tiny hole creates a faint projection of the scene on the inside of the "camera". You can make one yourself with a suitable cardboard box, a bit of foil, a needle and a sheet of photographic film. Exposure time ranges from a few seconds to a minute or two. In this case the artist used a layer of paint instead of a more traditional photosensitive material. The projected light will cause the paint to fade and change over time causing an image to appear over the course of centuries instead of minutes.
- brutus1213 3y ago
  I've wanted to make a pin hole cameras since I was a kid. I didn't realize the photographic film part .. now that makes sense! Where do you source that in North America these days? How do you handle it? I recall loading film into cameras as a kid .. that was exposed to light but then you moved over that part of the film? Presumably the part exposed to light is junk?
  - MadnessASAP 3y ago
    It's not film, it's the paper would project the negative onto to make a picture using an enlarger. It's not as readily available in this digital age but you should still be able to find it at a "good" camera store. I'd look for maybe single owner dedicated to craft type places vs chain dedicated to tech. You'll be wanting the B&W stuff, easier to develop and you can work with it under red lights instead total darkness. You'll also need 2 chemicals called "developer" and "fixer" suitable to the paper and distilled water to bath it in. Pinhole cameras are fun because you can build them in less then an hour for nearly free and it gets you hands on with the underlying principles of photography.
jrockway 3y ago
> Is there any difference between taking a 1000 year exposure and taking a photo every day for 1000 years and laying them ontop of eachother? There is a difference between taking a photo every day for 1000 years, what you end up with is, say, a 365,000 second exposure. This is an actual 1000 year exposure. The algorithm where you take 60 1/60th second exposures over the course of a second and then stitch them together is popular. There are many mobile apps that do this and try to use edge detection / "AI" to make them line up, so you can take handheld long exposure shots. (Spectre is an iOS app, but I'm sure there are others.) You can also do it yourself with a tripod and photoshop. The results are good, and it lets you take long exposures when you are constrained by having too much light and no ND filter / tiny aperture on your lens / etc. > Wouldn't it produce a solid white image after a single day? In general, reciprocity holds in photography. A 1 second exposure at f/8 is the same as a 2 second exposure at f/16 given the same sensor. (Films have a technical limitation called "reciprocity failure" for long exposures. Silver halide requires TWO photons to hit each atom, and the statistics of that aren't linear. This means that film exposures depend both on the shutter speed and ISO sensitivity; a properly exposed long exposure on film will often be longer than what the math dictates. The box that your film comes in will often give you a number to multiply your calculated exposure by.) So what they need is exceedingly low ISO film. A picture of a sunny scene would generally be exposed at f/16 and 1/<the ISO of the film>. A pinhole lens can't open that wide, they're more like f/180. That is "7 stops" less light than f/16, so would need a shutter speed of 1.3 seconds to capture the same image. Now you can see how insensitive the "film" in this camera is; it needs 31,536,000,000 seconds of exposure. That means it's 3.17e-11 ISO film they have in there. What quantum effects happen to film that insensitive, I don't know. They say it's paint fading, and I don't know what the rate is. It might end up being overexposed. (Film is usually OK being severely overexposed, the opposite of digital. No idea if paint fading behaves the same way as silver halide. Probably!) One other thing to think about; films often have differing sensitivity to different colors of light. Early film was overly sensitive to UV light, because it contains so much more energy than red light. Modern black and white film is pretty linear over the colors of light, so you end up with a picture that looks right to your eye. Paint does not have this carefully-designed chemistry, and is probably only sensitive to UV light, so that reduces the effective ISO of this camera setup even further. It won't respond to light you can see, only UV light. But, that works well enough to yield a recognizable image. (The problem in photography is that the sky contains too much UV, and you end up with an ugly white contrast-less sky. In this case, I don't think they care.)
dist-epoch 3y ago
Imagine something which slowly fades with light, like paint. Taking a photo every day is work, stuff can break. A passive sensor like paint would just sit there.
- izzydata 3y ago
  But how can they be so sure the paint won't fade completely after 1000 years? It could be gone after 10 years. Perhaps you could check on it as long as you don't move it even a millimeter.
  - ruined 3y ago
    the chemistry of photography is well-researched and involves simple calculations. it comes in many flavors, the product is repeatable and testable, and can be made very stable.
  - dist-epoch 3y ago
    We have 1000 years old buildings around. You can study parts which were in the sun versus shadow.

MadnessASAP 3y ago

It's a pinhole camera, a tiny hole creates a faint projection of the scene on the inside of the "camera". You can make one yourself with a suitable cardboard box, a bit of foil, a needle and a sheet of photographic film. Exposure time ranges from a few seconds to a minute or two. In this case the artist used a layer of paint instead of a more traditional photosensitive material. The projected light will cause the paint to fade and change over time causing an image to appear over the course of centuries instead of minutes.

brutus1213 3y ago
I've wanted to make a pin hole cameras since I was a kid. I didn't realize the photographic film part .. now that makes sense! Where do you source that in North America these days? How do you handle it? I recall loading film into cameras as a kid .. that was exposed to light but then you moved over that part of the film? Presumably the part exposed to light is junk?
- MadnessASAP 3y ago
  It's not film, it's the paper would project the negative onto to make a picture using an enlarger. It's not as readily available in this digital age but you should still be able to find it at a "good" camera store. I'd look for maybe single owner dedicated to craft type places vs chain dedicated to tech. You'll be wanting the B&W stuff, easier to develop and you can work with it under red lights instead total darkness. You'll also need 2 chemicals called "developer" and "fixer" suitable to the paper and distilled water to bath it in. Pinhole cameras are fun because you can build them in less then an hour for nearly free and it gets you hands on with the underlying principles of photography.

jrockway 3y ago

> Is there any difference between taking a 1000 year exposure and taking a photo every day for 1000 years and laying them ontop of eachother? There is a difference between taking a photo every day for 1000 years, what you end up with is, say, a 365,000 second exposure. This is an actual 1000 year exposure. The algorithm where you take 60 1/60th second exposures over the course of a second and then stitch them together is popular. There are many mobile apps that do this and try to use edge detection / "AI" to make them line up, so you can take handheld long exposure shots. (Spectre is an iOS app, but I'm sure there are others.) You can also do it yourself with a tripod and photoshop. The results are good, and it lets you take long exposures when you are constrained by having too much light and no ND filter / tiny aperture on your lens / etc. > Wouldn't it produce a solid white image after a single day? In general, reciprocity holds in photography. A 1 second exposure at f/8 is the same as a 2 second exposure at f/16 given the same sensor. (Films have a technical limitation called "reciprocity failure" for long exposures. Silver halide requires TWO photons to hit each atom, and the statistics of that aren't linear. This means that film exposures depend both on the shutter speed and ISO sensitivity; a properly exposed long exposure on film will often be longer than what the math dictates. The box that your film comes in will often give you a number to multiply your calculated exposure by.) So what they need is exceedingly low ISO film. A picture of a sunny scene would generally be exposed at f/16 and 1/<the ISO of the film>. A pinhole lens can't open that wide, they're more like f/180. That is "7 stops" less light than f/16, so would need a shutter speed of 1.3 seconds to capture the same image. Now you can see how insensitive the "film" in this camera is; it needs 31,536,000,000 seconds of exposure. That means it's 3.17e-11 ISO film they have in there. What quantum effects happen to film that insensitive, I don't know. They say it's paint fading, and I don't know what the rate is. It might end up being overexposed. (Film is usually OK being severely overexposed, the opposite of digital. No idea if paint fading behaves the same way as silver halide. Probably!) One other thing to think about; films often have differing sensitivity to different colors of light. Early film was overly sensitive to UV light, because it contains so much more energy than red light. Modern black and white film is pretty linear over the colors of light, so you end up with a picture that looks right to your eye. Paint does not have this carefully-designed chemistry, and is probably only sensitive to UV light, so that reduces the effective ISO of this camera setup even further. It won't respond to light you can see, only UV light. But, that works well enough to yield a recognizable image. (The problem in photography is that the sky contains too much UV, and you end up with an ugly white contrast-less sky. In this case, I don't think they care.)

dist-epoch 3y ago

Imagine something which slowly fades with light, like paint. Taking a photo every day is work, stuff can break. A passive sensor like paint would just sit there.

izzydata 3y ago
But how can they be so sure the paint won't fade completely after 1000 years? It could be gone after 10 years. Perhaps you could check on it as long as you don't move it even a millimeter.
- ruined 3y ago
  the chemistry of photography is well-researched and involves simple calculations. it comes in many flavors, the product is repeatable and testable, and can be made very stable.
- dist-epoch 3y ago
  We have 1000 years old buildings around. You can study parts which were in the sun versus shadow.