Using B&W film as eclipse filter

Cholentpot · Aug 21, 2017

I wasn't sure where to ask this as it's about film but maybe not taking photos.

I've been out of curiosity putting together some solar filters for the eclipse and sun viewing in general. I remember being told as a kid that negatives work. My research has turned up that you need to use exposed and developed B&W film double stacked. However I've seen also that modern B&W films don't have enough silver to filter anything.

I just so happen to have a bulk roll of ancient Tri-X from somewhere in the 70's or 80's. This is 'silver rich' and should work. Now, I have the regular glasses that are ISO rated and will be using those, I'm just wondering if using film would work.

Thanks.

Rick A · Aug 21, 2017

NO !! Let me reiterate that, NNNNOOOOOOOO !!!! The safest way to view an eclipse is a projector to look at the image on something other than looking directly at the sun. DO NOT TAKE ANY CHANCES WITH YOUR EYES. I wouldn't even trust those "supposed viewing glasses" that everyone is buying. Why any body would think a pair of cardboard framed cheap ass sunglasses from wally world will keep them safe is beyond me.

foc · Aug 21, 2017

Reminds me of an episode of the Simpsons where Homer gets a part time job testing pharmaceutical drugs.

"Who would want to buy a pill that makes you blind ?"
"Let marketing (department) worry about that."

RalphLambrecht · Aug 21, 2017

Cholentpot said:
I wasn't sure where to ask this as it's about film but maybe not taking photos.

I've been out of curiosity putting together some solar filters for the eclipse and sun viewing in general. I remember being told as a kid that negatives work. My research has turned up that you need to use exposed and developed B&W film double stacked. However I've seen also that modern B&W films don't have enough silver to filter anything.

I just so happen to have a bulk roll of ancient Tri-X from somewhere in the 70's or 80's. This is 'silver rich' and should work. Now, I have the regular glasses that are ISO rated and will be using those, I'm just wondering if using film would work.

Thanks.

Your eyesight is nothing to experiment with;To me the safest way is to use a pinhole and project the image with that onto a white piece of paper. NEVER look directly into the sun or, heavens forbid, into a telescope pointed at the sun. Also pointing a digital camera at the sun is one way to ruin the sensor or start a fire.
be safe and enjoy the eclipse. It's my third!

bdial · Aug 21, 2017

The film won't stop the UV, don't do it

sfaber17 · Aug 21, 2017

Cholentpot said:
I wasn't sure where to ask this as it's about film but maybe not taking photos.

I've been out of curiosity putting together some solar filters for the eclipse and sun viewing in general. I remember being told as a kid that negatives work. My research has turned up that you need to use exposed and developed B&W film double stacked. However I've seen also that modern B&W films don't have enough silver to filter anything.

I just so happen to have a bulk roll of ancient Tri-X from somewhere in the 70's or 80's. This is 'silver rich' and should work. Now, I have the regular glasses that are ISO rated and will be using those, I'm just wondering if using film would work.

Thanks.

I've done this in the 80's. Not that I stared at the sun for very long, but it didn't seem to hurt me. Not advising it.
Might have been plus-x. Of course some developers don't develop to full density so you have to be careful.
Color film is no good since it passes infrared. Not sure I believe that this method will pass UV. Try measuring with a UV densitometer sometime.

Cholentpot · Aug 21, 2017

Rick A said:
NO !! Let me reiterate that, NNNNOOOOOOOO !!!! The safest way to view an eclipse is a projector to look at the image on something other than looking directly at the sun. DO NOT TAKE ANY CHANCES WITH YOUR EYES. I wouldn't even trust those "supposed viewing glasses" that everyone is buying. Why any body would think a pair of cardboard framed cheap ass sunglasses from wally world will keep them safe is beyond me.

Millions upon millions world wide multiple times have used the cheapass cardboards. Is there an epidemic of blindness? I wanna see it with my eyes.

sfaber17 said:
I've done this in the 80's. Not that I stared at the sun for very long, but it didn't seem to hurt me. Not advising it.
Might have been plus-x. Of course some developers don't develop to full density so you have to be careful.
Color film is no good since it passes infrared. Not sure I believe that this method will pass UV. Try measuring with a UV densitometer sometime.

I've got some of that Tri-x soaking in rodinal for the next hour or so. Should be thick enough. I'm not looking to stare at the sun, just take glances to check it out. Staring is stupid as we all know.

Rick A · Aug 21, 2017

R E A D T H I S
https://tonic.vice.com/en_us/articl...ipse-burns-your-eyeballs?utm_source=tonicfbus

Cholenpot
As I'm about to turn 66, I very much feel and experience the effect of retinal damage from flash burns from looking (VERY BRIEFLY) at an arc welder, which is nowhere near as bad as looking at an eclipse. But hey, they're your eyes, you do what you want with them. You do the community a great disservice by coming on here and telling everyone you are sure that "just glimpsing " at it through your home made film viewer will be safe. You, pitiful fool, have no inkling how powerful the UV radiation really is.

Sal Santamaura · Aug 21, 2017

Cholentpot said:
...I've seen also that modern B&W films don't have enough silver to filter anything...

Nonsense. Here's what I posted in response to a Lounge question someone asked several days ago about whether he could use an R72 filter for viewing the eclipse:

Absolutely not!

Look at this graph of what comes from the sun:

https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg

Now look at the bandpass of an R72 filter:

http://www.randombio.com/infrared-filters.png

95% of everything above approximately 740nm would go straight to your retina!

Please use a pinhole projector to watch the eclipse on a piece of white cardboard. If anyone insists on looking directly at the sun, spend the next few days preparing a safe filter to do it through:

Fully expose some black and white film (not XP2 Super chromogenic) to daylight
Develop it well past the 'normal' developing time in an active developer like HC-110 or Ilfotec HC
After fixing, washing and drying, sandwich two layers and only look at the sun through that assembly.

Note that in the past I've fully exposed Delta 100 and developed it in Ilfotec HC for other purposes. Resulting negative density was in the neighborhood of 4.0. Two layers of approximately 4.0 density silver-gelatin film -- which will absorb the full spectrum -- is the minimum one should use for eye protection.

Please don't blind yourselves!

It's a bit late to start the process for today's eclipse, but there will be another one in less than two years, so be prepared.

Cholentpot · Aug 21, 2017

Rick A said:
R E A D T H I S
https://tonic.vice.com/en_us/articl...ipse-burns-your-eyeballs?utm_source=tonicfbus

Cholenpot
As I'm about to turn 66, I very much feel and experience the effect of retinal damage from flash burns from looking (VERY BRIEFLY) at an arc welder, which is nowhere near as bad as looking at an eclipse. But hey, they're your eyes, you do what you want with them. You do the community a great disservice by coming on here and telling everyone you are sure that "just glimpsing " at it through your home made film viewer will be safe. You, pitiful fool, have no inkling how powerful the UV radiation really is.

Hey hey! Take it easy. Would you call me a pitiful fool to my face?

I have the proper safety googles and a nice thick piece of welders glass. I'm not using the homemade thing for the eclipse, I might use it as a front filter for a lens in the future though.

Sal Santamaura said:
Nonsense. Here's what I posted in response to a Lounge question someone asked several days ago about whether he could use an R72 filter for viewing the eclipse:

Absolutely not!

Look at this graph of what comes from the sun:

https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg
Now look at the bandpass of an R72 filter:

http://www.randombio.com/infrared-filters.png
95% of everything above approximately 740nm would go straight to your retina!

Please use a pinhole projector to watch the eclipse on a piece of white cardboard. If anyone insists on looking directly at the sun, spend the next few days preparing a safe filter to do it through:

Fully expose some black and white film (not XP2 Super chromogenic) to daylight

Develop it well past the 'normal' developing time in an active developer like HC-110 or Ilfotec HC

After fixing, washing and drying, sandwich two layers and only look at the sun through that assembly.

Note that in the past I've fully exposed Delta 100 and developed it in Ilfotec HC for other purposes. Resulting negative density was in the neighborhood of 4.0. Two layers of approximately 4.0 density silver-gelatin film -- which will absorb the full spectrum -- is the minimum one should use for eye protection.

Please don't blind yourselves!
It's a bit late to start the process for today's eclipse, but there will be another one in less than two years, so be prepared.

So my cookery of Tri-x in rodinal 1:50 for over and hour would do the job? I'm a DIY guy in general.

I bought what I need back before the rush. I'm no idiot I was just wondering if film blocks the UV rays. I do solar photography from time to time and was just wondering if film would make a good filter. We're getting 83% coverage here. in 2024 we'll be getting 100% though, this is a dry run for me. If what I'm trying works this time, next time I'll get a better lens and plan the whole thing out in advance.

Rick A · Aug 21, 2017

http://www.instructables.com/id/Cardboard-Box-Eclipse-Viewer/

faberryman · Aug 21, 2017

Cholentpot said:
I'm a DIY guy in general.

How are you at DIY retinal tissue regeneration?

I am extremely protective of my vision. I wear glasses (for distance) instead of having lasik surgery. Sure, the chances of a problem are miniscule, but these are the only eyes I've got. So looking at an eclipse using some DIY filters is insane. I am using a pinhole viewing box. NASA will publish some awesome images.

Sal Santamaura · Aug 21, 2017

Cholentpot said:
...I was just wondering if film blocks the UV rays...

As long as it's not chromogenic (i.e. XP2 Super), fully exposed and overdeveloped black and white film will attenuate the complete spectrum. It's silver that does that job. Dyes, such as found in neutral density filters and XP2 Super, can't accomplish this.

I strongly suggest that, if anyone insists on looking directly rather than the much wiser pinhole projection approach, they not only employ two layers of film, but also make sure there's a lot of it in front of their eyes. I'd use at least sheet film. The problem is that, with so much broad-spectrum attenuation, the irises will open fairly wide. Then, if there's any misalignment between viewing filter, eyes and sun, a full blast of sunlight can be permitted to attack vision. Better to have a very large filter over one's face and thereby prevent stray light leakage.

One last time, for everyone reading this, the best option is a pinhole projector.

Cholentpot · Aug 21, 2017

Sal Santamaura said:
As long as it's not chromogenic (i.e. XP2 Super), fully exposed and overdeveloped black and white film will attenuate the complete spectrum. It's silver that does that job. Dyes, such as found in neutral density filters and XP2 Super, can't accomplish this.

I strongly suggest that, if anyone insists on looking directly rather than the much wiser pinhole projection approach, they not only employ two layers of film, but also make sure there's a lot of it in front of their eyes. I'd use at least sheet film. The problem is that, with so much broad-spectrum attenuation, the irises will open fairly wide. Then, if there's any misalignment between viewing filter, eyes and sun, a full blast of sunlight can be permitted to attack vision. Better to have a very large filter over one's face and thereby prevent stray light leakage.

One last time, for everyone reading this, the best option is a pinhole projector.

I just wanted some info about it. Is it possible, yes. Should you do it? Maybe but probably not. Great. Thanks.

I'd suppose using some sheet film and then looking through some welding glass would be safer than anything else. If any light would come through at that point...I guess curiosity fried the cats retinas.

Marcelo Paniagua · Aug 21, 2017

Possible, but not recommended.

Like it been said, its your only pair of eyes. Its the main pair of your body you use to do photography, and I suppose you like seeing and making photos (you are on a photography forum afterall ).

Take good care of yourself, don't risk something as precious as your eyes for something as a blurry sun image (that's what you are going to see using film).

Best regards

Marcelo Paniagua.

BrianShaw · Aug 21, 2017

Well, its come-and-gone in my area (we were in 60% eclipse only). The world did not come to an end and I saw a lot of people looking with pinholes... smart people that they are. Did not see anyone with glasses here... I work with too many nerdy engineers and scientists that either know what's safe and what's not, or are scaredy of eye damage.

Slixtiesix · Aug 21, 2017

Like others said, don´t do it!

Sal Santamaura · Aug 21, 2017

Sal Santamaura said:
...in the past I've fully exposed Delta 100 and developed it in Ilfotec HC for other purposes. Resulting negative density was in the neighborhood of 4.0. Two layers of approximately 4.0 density silver-gelatin film -- which will absorb the full spectrum -- is the minimum one should use for eye protection...

Sal Santamaura said:
...I strongly suggest that, if anyone insists on looking directly rather than the much wiser pinhole projection approach, they not only employ two layers of film, but also make sure there's a lot of it in front of their eyes. I'd use at least sheet film. The problem is that, with so much broad-spectrum attenuation, the irises will open fairly wide. Then, if there's any misalignment between viewing filter, eyes and sun, a full blast of sunlight can be permitted to attack vision. Better to have a very large filter over one's face and thereby prevent stray light leakage...

Now that the eclipse is over, here's a follow up. I still have an 8x10-inch sheet of the Delta 100 negative mentioned above that hadn't been cut down. My densitometer's 1.0mm aperture limits what it can measure to 3.5 maximum, and it hit top of scale with this negative. That's why I estimated the density at 4.0.

My first attempt to look at the sun through two layers (I folded it in half) revealed no image at all. It was as opaque as being inside the house and looking up through the ceiling, attic and roof. Unfolding it and looking through one layer was just right. I suspect that typical black and white film/developer combinations, which might top out at densities lower than 4.0, would be more appropriate for doubling.

For those who argue that a metal foil is necessary, recognize that density of the film described here is a result of metallic silver. There's no question it absorbs the full solar spectrum and is safe. But only if prepared and used properly.

Cholentpot · Aug 21, 2017

Well I did it and I'm not blind.

I did screw up the long exposure though, I think I got the main gig but missed the end. Lessons learned and I'm awaiting 2024!

Rick A · Aug 21, 2017

https://www.slrlounge.com/solar-ecl...-a-6-second-exposure-burn-a-hole-in-a-sensor/

Cholentpot · Aug 21, 2017

Rick A said:
https://www.slrlounge.com/solar-ecl...-a-6-second-exposure-burn-a-hole-in-a-sensor/

Shot at f/22 with a piece of welders glass on a 80mm lens, 6x6 body. While that video is very entertaining and informative I don't own a 400 f2.8 nor do I think I ever will.

If I burned my roll of Shanghai I guess I'm out about $2. Ruined the camera? Maybe $50. I'd call it safe.

newcan1 · Aug 22, 2017

Cholentpot said:
Well I did it and I'm not blind.

I did screw up the long exposure though, I think I got the main gig but missed the end. Lessons learned and I'm awaiting 2024!

I did too. I used it on a telephoto lens and on a telescope and took some great shots -- that my eyes can still see. People have observed eclipses long before ISO standards were invented. I am surprised people drive cars anymore - they might die.

Fraunhofer · Aug 22, 2017

newcan1 said:
I did too. I used it on a telephoto lens and on a telescope and took some great shots -- that my eyes can still see. People have observed eclipses long before ISO standards were invented. I am surprised people drive cars anymore - they might die.

I've done that with T-max in the 1990's, as a filter for a telephoto lens, double stacked. As far as I can tell, no vision damage (still 20/20).

Disclaimer: I am not saying you should do this, and if you do, whatever happens is your own fault.

Cholentpot · Aug 22, 2017

newcan1 said:
I did too. I used it on a telephoto lens and on a telescope and took some great shots -- that my eyes can still see. People have observed eclipses long before ISO standards were invented. I am surprised people drive cars anymore - they might die.

Fraunhofer said:
I've done that with T-max in the 1990's, as a filter for a telephoto lens, double stacked. As far as I can tell, no vision damage (still 20/20).

Disclaimer: I am not saying you should do this, and if you do, whatever happens is your own fault.

No no! I'm a pitiful fool.

RalphLambrecht · Aug 23, 2017

Sal Santamaura said:
As long as it's not chromogenic (i.e. XP2 Super), fully exposed and overdeveloped black and white film will attenuate the complete spectrum. It's silver that does that job. Dyes, such as found in neutral density filters and XP2 Super, can't accomplish this.

I strongly suggest that, if anyone insists on looking directly rather than the much wiser pinhole projection approach, they not only employ two layers of film, but also make sure there's a lot of it in front of their eyes. I'd use at least sheet film. The problem is that, with so much broad-spectrum attenuation, the irises will open fairly wide. Then, if there's any misalignment between viewing filter, eyes and sun, a full blast of sunlight can be permitted to attack vision. Better to have a very large filter over one's face and thereby prevent stray light leakage.

One last time, for everyone reading this, the best option is a pinhole projector.

+1000!I'm starting to buy stock in blind-dog breeding. Hey guys, this is not too difficult; build a pinhole projector to enjoy the eclipse without blinding yourself or others, But,now, that the eclipse is over,plese report on actual experiences if you still have your vision and are able to see the keyboard.

Using B&W film as eclipse filter

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