Author Topic: Radiation and photographic film  (Read 13377 times)

Offline onebigmonkey

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Re: Radiation and photographic film
« Reply #30 on: June 20, 2013, 01:27:32 PM »
By radar-tracking, I suppose you mean radio-based tracking? It would be a lot to ask for a skin-radar-return to be measurable at that distance.

I've spent most of today trying to track down the original references I read when researching the Orbiter program, and while most of them mention tracking, they aren't very specific about how it was done. You're right of course! Just wish I could find the articles I'd read!

Offline bknight

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Re: Radiation and photographic film
« Reply #31 on: March 24, 2016, 11:20:22 PM »
I dug this one up after a poster indicated that all images from Apollo had some radiation artifacts.  I was unaware of any radiation artifacts on any of them, is/was there a minor amount of damage that I have missed or glossed over viewing those images?
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Offline Allan F

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Re: Radiation and photographic film
« Reply #32 on: March 25, 2016, 12:46:16 AM »
I have never identified any radiation artefacts. There are occasional scratches in the emulsion, some of which appear to have happened in the development process. IF any radiation had reached the film, it would apply a whitish sheen to the pictures - make the black parts slightly grey. And it would be evenly distributed across the film. A single radiation event (a single charged particle or photon) does not carry enough energy to make any visible impression on the film. Only a distributed field of a certain minimum intensity would do anything. I have yet to calculate the light energy needed to affect an ISO 100 film and darken it to the standard 18% (which should be doable, using a combination of shutter speed and apeture known to work in daylight), and then I need some information about how the different types of radiation would affect the film - and of course the attenuation effects of the camera and magazine body. Bob B has already shown how the command module was sufficiently shielded to protect the astronauts - and the film was further protected by being stored in metal boxes.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline smartcooky

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Re: Radiation and photographic film
« Reply #33 on: March 25, 2016, 02:41:35 AM »
That's what I did - and it has been dragging on for about 2 weeks now. Everytime I ask a pertinent question, I get foul language in return.

Example: I asked: "AND you still have to quantify the amount of your particles - one particle on the entire journey won't cause enough radiation to make a spot on even unshielded film. You need to tell us the number of particles in a cubic centimeter"

and got: "The number of particles is E = MC2 to the 33rd power x the number of Freemasons on the US Fed board by birth, divided by their greed & contempt for constitutional normalities, then multiplied by the collective debt of the US Taxpayer over their US Federal Deficit after the entire NASA budget since the faked Apollo landings was added in triplicate. Secondary radiation from high-energy particles from old nova make your Venus photo as impossible as a magic bullet going to Uranus via Dallas Texas."

If that is the kind of response you get to reasonable questions then you will be wasting your time. This sort of person as a troll (or a nutcase, or both). They will never accept what you have to say no matter what you say.   
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Offline onebigmonkey

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Re: Radiation and photographic film
« Reply #34 on: March 25, 2016, 03:29:57 AM »
I wonder if they were referring to the 'blue dots' you seen on the images, many of which are mistaken for stars?

Offline bknight

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Re: Radiation and photographic film
« Reply #35 on: March 25, 2016, 08:29:27 AM »
I'm not sure, but this is his comments, and he isn't a hoaxer.
Quote
Although you have been told an a number of occasions that ALL APOLLO PHOTOS exhibit some radiation damage
He is arguing with a hoaxer on images.
I'm trying to get the hoaxer to calculate the radiation received during a typical Apollo mission, radiation is his one big hang-up on the missions.

EDIT: changed wording to clarify my sentence.
« Last Edit: March 25, 2016, 08:50:27 AM by bknight »
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Offline Allan F

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Re: Radiation and photographic film
« Reply #36 on: March 25, 2016, 05:44:33 PM »
I wonder if they were referring to the 'blue dots' you seen on the images, many of which are mistaken for stars?

Those are what I suspect are damage to the photographic emulsion - caused by dragging wet film over an edge or something.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline ka9q

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Re: Radiation and photographic film
« Reply #37 on: March 25, 2016, 06:11:40 PM »
I wonder if they were referring to the 'blue dots' you seen on the images, many of which are mistaken for stars?
A while ago I proposed that these blue dots were caused by superficial dust scratches on the emulsion of the film.

Color films consist of a sandwich of four emulsion layers on a plastic base (acetate, polyester, etc). The topmost layer (the one closest to the lens) is sensitive to blue light only. Below that is a yellow filter. Next is a layer sensitive to green and blue light, and below that is a layer sensitive to red and blue light.

The yellow filter is needed to remove blue light because all chemical emulsions are sensitive to it. This ensures that the green layer sees only green light, to which it responds, and red light, which it ignores. The red layer on the bottom then responds to the red but not the green.

Ektachrome is a positive process, meaning that the developed image looks like the original (it's not a color negative).

It's also called a "reversal" process, which can be a little confusing; "reversal" refers to reversing the usual film negative to a positive by first developing the exposed silver halide to a metallic silver negative, bleaching out the silver and then fogging and developing the remaining, formerly unexposed silver halide to produce a positive image.

The silver remains as the black in a black and white image, but in color films the silver is only used to trigger the formation of the color dyes that actually form the image; all the silver is ultimately removed. Complementary dyes are formed in each layer: yellow dye in the blue layer, magenta in the green layer and cyan in the red layer.

So if the blue layer in the undeveloped film is removed by scratching, then it will remain clear throughout the development process. If the image is otherwise black, the underlying green and red layers will remain unexposed so after reversal they will produce dense magenta and cyan filters that stop green and red light while passing blue. So the scratch turns into a blue dot.

If the scratch goes through all the layers of the emulsion, it will remain completely clear and appear white after processing. You see those too in many of the Apollo lunar surface images.

Offline VQ

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Re: Radiation and photographic film
« Reply #38 on: March 26, 2016, 02:44:07 AM »
I have never identified any radiation artefacts. There are occasional scratches in the emulsion, some of which appear to have happened in the development process. IF any radiation had reached the film, it would apply a whitish sheen to the pictures - make the black parts slightly grey. And it would be evenly distributed across the film. A single radiation event (a single charged particle or photon) does not carry enough energy to make any visible impression on the film. Only a distributed field of a certain minimum intensity would do anything. I have yet to calculate the light energy needed to affect an ISO 100 film and darken it to the standard 18% (which should be doable, using a combination of shutter speed and apeture known to work in daylight), and then I need some information about how the different types of radiation would affect the film - and of course the attenuation effects of the camera and magazine body. Bob B has already shown how the command module was sufficiently shielded to protect the astronauts - and the film was further protected by being stored in metal boxes.

I seem to recall imaging individual beta decays of 35S when helping with biochemistry research (autoradiography). The media with the tracer was pressed tight up against the film. It's been a long while since then and I am a little fuzzy on the details; is the film used for that sort of imaging substantially more sensitive to radiation than the Apollo film?

Offline bknight

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Re: Radiation and photographic film
« Reply #39 on: March 26, 2016, 10:43:22 AM »
I wonder if they were referring to the 'blue dots' you seen on the images, many of which are mistaken for stars?
A while ago I proposed that these blue dots were caused by superficial dust scratches on the emulsion of the film.

Color films consist of a sandwich of four emulsion layers on a plastic base (acetate, polyester, etc). The topmost layer (the one closest to the lens) is sensitive to blue light only. Below that is a yellow filter. Next is a layer sensitive to green and blue light, and below that is a layer sensitive to red and blue light.

The yellow filter is needed to remove blue light because all chemical emulsions are sensitive to it. This ensures that the green layer sees only green light, to which it responds, and red light, which it ignores. The red layer on the bottom then responds to the red but not the green.

Ektachrome is a positive process, meaning that the developed image looks like the original (it's not a color negative).

It's also called a "reversal" process, which can be a little confusing; "reversal" refers to reversing the usual film negative to a positive by first developing the exposed silver halide to a metallic silver negative, bleaching out the silver and then fogging and developing the remaining, formerly unexposed silver halide to produce a positive image.

The silver remains as the black in a black and white image, but in color films the silver is only used to trigger the formation of the color dyes that actually form the image; all the silver is ultimately removed. Complementary dyes are formed in each layer: yellow dye in the blue layer, magenta in the green layer and cyan in the red layer.

So if the blue layer in the undeveloped film is removed by scratching, then it will remain clear throughout the development process. If the image is otherwise black, the underlying green and red layers will remain unexposed so after reversal they will produce dense magenta and cyan filters that stop green and red light while passing blue. So the scratch turns into a blue dot.

If the scratch goes through all the layers of the emulsion, it will remain completely clear and appear white after processing. You see those too in many of the Apollo lunar surface images.
I have seen the blue dots on some of the images, but never thought they were radiation artifacts, since there were many more images that did not contain a blue dot.  The scratch concept is probably a reasonable guesstimate.
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Offline bknight

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Re: Radiation and photographic film
« Reply #40 on: March 29, 2016, 11:24:42 AM »
The proponent posted another assertion that all the film has radiation artifacts
Quote
All of the Apollo lunar surface photos show some radiation damage, although this is not obvious with the enhanced versions we usually see on the net or in publications. The problem is that MOST people have never seen a photo with radiation damage, and do not understand that different types of films ( reversal, negative,color, black and white, slow fast..) react to radiation in very different ways..

Any thoughts from the film experts?
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Offline Allan F

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Re: Radiation and photographic film
« Reply #41 on: March 29, 2016, 03:25:42 PM »

I seem to recall imaging individual beta decays of 35S when helping with biochemistry research (autoradiography). The media with the tracer was pressed tight up against the film. It's been a long while since then and I am a little fuzzy on the details; is the film used for that sort of imaging substantially more sensitive to radiation than the Apollo film?

Problem is, only x-ray/gamma radiation would ever reach the film. Particles like alpha and beta would be stopped by the body of the camera and the lens. Perhaps Bob B. can do us a favor here?
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline Bob B.

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Re: Radiation and photographic film
« Reply #42 on: March 29, 2016, 06:10:00 PM »
Problem is, only x-ray/gamma radiation would ever reach the film. Particles like alpha and beta would be stopped by the body of the camera and the lens. Perhaps Bob B. can do us a favor here?

I don't see a specific question here, so I don't know exactly what I'm being asked to comment on?

Generally speaking, I would expect that beta radiation <1 MeV would be blocked by the camera body and lens.  Alpha radiation wouldn't be a problem at all.  I think it possible that beta radiation >1 MeV could penetrate through to the film, but that would only be an issue when the camera is outside on the lunar surface.  I have no idea how much or how strong beta radiation is in that environment, though I suspect not much.  Soft x-rays should also be easily blocked.  Hard x-rays, if they exist, would be a problem.  Inside the spacecraft, I feel reasonable confident that the film would be plenty safe, even when passing through the Van Allen Belts.

If you want some rough numbers, 1 mm of aluminum will block electrons ≤0.7 MeV, and will attenuate 99.9% of 10 keV x-rays.

That's my 2¢ for what it's worth.  Keep in mind that I'm no expert.

Offline bknight

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Re: Radiation and photographic film
« Reply #43 on: March 29, 2016, 06:51:26 PM »

I don't see a specific question here, so I don't know exactly what I'm being asked to comment on?

Generally speaking, I would expect that beta radiation <1 MeV would be blocked by the camera body and lens.  Alpha radiation wouldn't be a problem at all.  I think it possible that beta radiation >1 MeV could penetrate through to the film, but that would only be an issue when the camera is outside on the lunar surface.  I have no idea how much or how strong beta radiation is in that environment, though I suspect not much.  Soft x-rays should also be easily blocked.  Hard x-rays, if they exist, would be a problem.  Inside the spacecraft, I feel reasonable confident that the film would be plenty safe, even when passing through the Van Allen Belts.

If you want some rough numbers, 1 mm of aluminum will block electrons ≤0.7 MeV, and will attenuate 99.9% of 10 keV x-rays.

That's my 2¢ for what it's worth.  Keep in mind that I'm no expert.
The issue is a Apollo proponent is arguing with a hoaxer along with myself, and he(proponent) believes all images have some radiation damage.  See above post, but here it is
Quote
All of the Apollo lunar surface photos show some radiation damage, although this is not obvious with the enhanced versions we usually see on the net or in publications. The problem is that MOST people have never seen a photo with radiation damage, and do not understand that different types of films ( reversal, negative,color, black and white, slow fast..) react to radiation in very different ways..
I never have seen any, but I might hove glossed over any radiation effects, I was just posting the question for our proponent individuals.
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Offline ka9q

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Re: Radiation and photographic film
« Reply #44 on: March 29, 2016, 07:11:27 PM »
I could envision that cosmic rays might also penetrate the camera or magazine and hit the film, but I've never seen any evidence of that in the Apollo images. I'd expect them to leave white traces, but because the paths are random I'd expect random streaks, not just dots.