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Infrared 35mm film (Rollei IR 400)


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Hey


Im doing lighting test , for a project on infrared film, 35mm, indoor shooting.



we're trying a verity of light sources in order to get the right and effective light for this kind of project.


I know that mostly infrared used on outdoor shooting, under the open sky, but here, we also want to shoot some indoor night scenes on this reel.



just some few facts about this material:



the light spectrum we are trying to get is between 720-820 nm (nanometer), which also being called "invisible light", since this wave spectrum aint visible to the seeing eye.



thats why we use gel filters on all of our main light sources.



till now we used 5K's, Par 64's, 1K's, some lightpad panels, but(!),


what im trying to find, is a light source which will speak the same language of the ifrared wave spectrum, and not just some regular cinema classic lights.



1. does anyone here knows, heard, or experienced this kind of situation?


2. can i work with infrared light with diffusions? like we regulary do on set?


3. what is the effect of bounce through white poly board with infrared light? can we bounce regulary like we used too?



thnx ^_^


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Hello,

When shooting IR there are many thing to watch out for. Since you want to shoot "near ir" (720-820nm) lens focus should not be that much of an issue and neither will be heat radiation. The only focus problem will be that the film you are using is sensitive to visible light and so you are going to have to use a filter. The filtering will screw with focus and you will have a very hard time focusing through the lens. Metering will be quite problem, you will have to just shoot tests. If you can, find a spectral output graph of the lights you have. Some have IR/UV filter glass coatings. Fluorescents & visible LEDs will wave no IR output. For the easiest lighting, either buy or create an LED panel. LEDs with that spectral output are very common. If you use these and limit visible light while shooting you can get away with not using a filter. Then you may be able to focus with visible lights then lower them to a minimum and activate the IR. You can diffuse and bounce. You will have to look at the diffusers transmission graph and see which one will be best. The best thing to do is purchase a cheap set of night vision goggles. Most cheap ones have a single LED illumination (which you can turn off) and operate in the spectrum you are going to shoot. That will let you see the diffusion / bounce.

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Thnx alot for your comment.

We plan on working with visible light speels from the light sourses around us, since its a documentary we are shooting. We try as much as possible not to interfere with the already exist light. That why we are looking for infrared light sources which could work without geting tomuch attention from the surroundings.

That why I started this experimental research about infrared lighting, so i could understand better how i control ambiance light, and key light.

 

This goggle idea is amazing. Thnx alot.

I tried look for this kind of meter which will give me some info about the wavelength of he lights around my location, so i could use it as if it was a light meter.

Do you think this nightvision goggle can be configurate for this specific light spectrum we are looking for?

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The low cost consumer night vision goggles will have an led for illumination you can turn off or on and are sensitive in the spectral range you are shooting. The cheaper ones I speak of are really just high gain near ir imagers. If they have no ir illumination source, they dont work. The ones the cops/military use are sensitive in much longer and wider range of wavelengths. On the consumer ones the LED built in is about where you are shooting 750 -900nm and will vary by goggle manufacturer. You could turn off the LED and use a r72 filter or something on the goggles to see the spectrum the film will see and you cant. We have some here at the lab. They are in the range you are shooting and I will find their name and part number. When in total darkness you can see some red emission from the built in LED as its spectral output has skirts and so do our eyes. We have to use them here because Kodak stopped making 72 internegative. It is used to print from color reversal/pos to color negative. They replaced 72 with 73 which is the 03 50D emulsion on top of estar base with no rem jet. That means no safe lights(total darkness) in the printer room. Color camera neg is not really sensitive above 690nm, lab intermediate stocks around 740nm. So while printing interneg, the operator wears the goggles to monitor the printer.

Edited by Thomas Aschenbach
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