Film exposed to light

Peter Rigeti · Mar 3, 2020

Hey all,

My question would be, does infra(red) light damage negative film? I think, since it's not visible light, it doesn't.
Because i would use it in darkroom, when inserting film into the tank.

Thanks for your help.
Have a nice day

Vaughn · Mar 4, 2020

People use infra red goggles to handle film in the dark. As long as it is not infra red-sensitive film, of course.

Might check out this thread I searched for: https://www.photrio.com/forum/threads/cheap-night-vision-device-for-darkroom-use.36022/#post-520223

RalphLambrecht · Mar 4, 2020

Peter Rigeti said:
Hey all,

My question would be, does infra(red) light damage negative film? I think, since it's not visible light, it doesn't.
Because i would use it in darkroom, when inserting film into the tank.

Thanks for your help.
Have a nice day

First, all light is visible. That is the definition of light. Also, I'm not sure that not-infrared film is completely 'blind' to Infrared radiation. Therefore, complete darkness is recommended for film processing.

Peter Rigeti · Mar 4, 2020

RalphLambrecht said:
First, all light is visible. That is the definition of light. Also, I'm not sure that not-infrared film is completely 'blind' to Infrared radiation. Therefore, complete darkness is recommended for film processing.

You are wrong, uv and infrared are non visible light. Google it.

Agulliver · Mar 4, 2020

It will depend on the spectral sensitivity of the film you're handling. Some film is sensitive to IR...Ilford SFX and any film derived from aviation film (eg Rollei Retro 400S). THese would likely be ruined. Other film may have low sensitivity to IR and the only way is to try.

Maybe you could expose a small amount in the dark room to IR, and develop the piece of film to see if there's any fogging.

lensman_nh · Mar 4, 2020

Generally speaking, if the light source has a wavelength longer than about 750 nM then film will not be fogged. Most datasheets have a spectral sensitivity curve. This one is for Ilford FP4+.

Above about 675 nm it's insensitive. Incidentally, a healthy human eye can see from violet at about 400nM through to deep red at about 700 nM wavelength. This also shows why a UV cut filter is useful. The film is sensitive to light we don't see at the UV end, so using a UV cut filter makes the scene more like we saw it.

Also another useless fact, a lot of astrophotograpy of emission nebulae happens in deep red around 656 nM. FP4+ is pretty insensitive there, and wouldn't be a good choice if you wanted to use film.

J.

RalphLambrecht · Mar 5, 2020

Peter Rigeti said:
You are wrong, uv and infrared are non visible light. Google it.

You google it or better wiki it. light is , per definition, that range of electromagnetic radiation that our eyes are sensitive to, roughly 400-700nm. UV and infrared radiation are outside that range ,and therefore, not light but just that UV and infrared radiation. There is no such thing as non-visible light.

John Salim · Mar 5, 2020

Peter Rigeti said:
Hey all,

My question would be, does infra(red) light damage negative film? I think, since it's not visible light, it doesn't.
Because i would use it in darkroom, when inserting film into the tank.

Thanks for your help.
Have a nice day

I use infra-red goggles on a daily basis and can tell you they are completely safe with all standard colour or B&W negative and reversal films ( except infra-red films of course ).

John S

Andrew O'Neill · Mar 5, 2020

It's fine with conventional pan film. SFX, Rollie IR, Efke IR, HIE that I have on hand, nope.

Vaughn · Mar 5, 2020

RalphLambrecht said:
You google it or better wiki it. light is , per definition, that range of electromagnetic radiation that our eyes are sensitive to, roughly 400-700nm. UV and infrared radiation are outside that range ,and therefore, not light but just that UV and infrared radiation. There is no such thing as non-visible light.

Such a human-based definition! There are beasties that can see light that we (humans) can not see...or...they can sense radiation of wavelengths the human eye are not sensitive to. Take your pick. The sun will never set on the America...but the earth will rotate and the sun will not be shining on our side of the earth for a while.

warden · Mar 5, 2020

lensman_nh said:
This also shows why a UV cut filter is useful. The film is sensitive to light we don't see at the UV end, so using a UV cut filter makes the scene more like we saw it.

I learned something today. Thank you!

RalphLambrecht · Mar 5, 2020

Vaughn said:
Such a human-based definition! There are beasties that can see light that we (humans) can not see...or...they can sense radiation of wavelengths the human eye are not sensitive to. Take your pick. The sun will never set on the America...but the earth will rotate and the sun will not be shining on our side of the earth for a while.

Well, I am not responsible for the definition of light but, it is what it is. Humans practice science and humans create these definitions. Consequently, it's understandable with the definitions tend to be human-based.

Vaughn · Mar 5, 2020

You are absolved of responsibility, Ralph...Tongue-in-cheek. We do have machines that allow us to see non-visible radiation visually...brave new world...

Luckless · Mar 6, 2020

A few years ago I had been playing around with some ultrasonic scanning tools to generate real time 3D mapping of things.

If kept to a small space it might be enough to have a workable resolution without excessive costs. I haven't kept up with the latest developments, and the gear I was working with at the time was already on the lower end of things, but it seemed like it would be more than enough to give some general guidance over just 'fumbling around in the dark'.

Of course the question I don't yet know is: Can something like bombarding undeveloped film with tightly focused ultrasonic sound waves cause some manner of reaction? I've always been told that pressure can result in damage to negatives with 120 roll film, but I've never put that to the test, so I have to assume that there is at least some potential for risk with physical interactions...

Vaughn said:
You are absolved of responsibility, Ralph...Tongue-in-cheek. We do have machines that allow us to see non-visible radiation visually...brave new world...

Almost like we update scientific definitions based on changes in understanding of the fundamental nature of things...

Probably why we have both the terms light, and visible light in modern English. Can't really see a justification for the extension to the term light if it was already and forever exclusive to the visible parts of it...

Would also mean some rather awkward conversations to be had with anyone working with IR Lighting...

Film exposed to light

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