IR films using IR light

anon s · Sep 18, 2018

Hello,

anyone got experience to take IR films using IR lights?

Normally I use 350-400w strobe with softbox when I take portrait with IR films (ISO 12-25) inside.
Now I am thinking my traveling gear to do the same shooting but something compact.
I am checking up Godox AD360 ... but I have just thought about IR lights.... if it works?
It might be more smaller or compact than AD360...

many thanks,

AgX · Sep 19, 2018

What do you understand by "IR lights"?

Ces1um · Sep 19, 2018

Do you mean a heater or one of those heat lamp bulbs? Longer infrared radiation is just heat.

Anon Ymous · Sep 19, 2018

A typical tungsten lamp emits a lot of IR radiation, much more than in the visible spectrum.

Ces1um · Sep 19, 2018

Anon Ymous said:
A typical tungsten lamp emits a lot of IR radiation, much more than in the visible spectrum.

I could be wrong, but isn't it on the wrong end of the spectrum though? IR is around 700nm to 1mm and tungsten is like 350 to 700?
http://www.graphics.cornell.edu/online/measurements/source-spectra/intsphere.jpg for tungsten
or
https://www.google.com/imgres?imgur...hUKEwiptoupisfdAhVKhOAKHeccDh4Q9QEwAHoECAYQBg
and infrared is:
https://en.wikipedia.org/wiki/Infrared
first paragraph:
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions [1][2][3][4]). It is sometimes called infrared light. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz)[5] Most of the thermal radiation emitted by objects near room temperature is infrared. Like all EMR, IR carries radiant energy, and behaves both like a wave and like its quantum particle, the photon.

Anon Ymous · Sep 19, 2018

Ces1um said:
I could be wrong, but isn't it on the wrong end of the spectrum though? IR is around 700nm to 1mm and tungsten is like 350 to 700?
http://www.graphics.cornell.edu/online/measurements/source-spectra/intsphere.jpg for tungsten
or
https://www.google.com/imgres?imgur...hUKEwiptoupisfdAhVKhOAKHeccDh4Q9QEwAHoECAYQBg
and infrared is:
https://en.wikipedia.org/wiki/Infrared
first paragraph:
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions [1][2][3][4]). It is sometimes called infrared light. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz)[5] Most of the thermal radiation emitted by objects near room temperature is infrared. Like all EMR, IR carries radiant energy, and behaves both like a wave and like its quantum particle, the photon.

The charts you linked to show an upwards slope, but stops around 700nm. In reality, it continues rising, reaches a peak, then goes downwards, making a bell shaped chart if IR spectrum is included.

Ces1um · Sep 19, 2018

Anon Ymous said:
The charts you linked to show an upwards slope, but stops around 700nm. In reality, it continues rising, reaches a peak, then goes downwards, making a bell shaped chart if IR spectrum is included.

Thanks for the clarification! Good to know.

RalphLambrecht · Sep 19, 2018

Ces1um said:
I could be wrong, but isn't it on the wrong end of the spectrum though? IR is around 700nm to 1mm and tungsten is like 350 to 700?
http://www.graphics.cornell.edu/online/measurements/source-spectra/intsphere.jpg for tungsten
or
https://www.google.com/imgres?imgur...hUKEwiptoupisfdAhVKhOAKHeccDh4Q9QEwAHoECAYQBg
and infrared is:
https://en.wikipedia.org/wiki/Infrared
first paragraph:
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions [1][2][3][4]). It is sometimes called infrared light. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz)[5] Most of the thermal radiation emitted by objects near room temperature is infrared. Like all EMR, IR carries radiant energy, and behaves both like a wave and like its quantum particle, the photon.

this is a bit confusing because, all light is visible light!Actually, the definition of light is t:the visible part of the electromagnetic radiation.According to that, there is no such thing as uv or IR light ;only UV and IR radiation.

Wallendo · Sep 19, 2018

IR lights are found routinely on security systems, some video cameras, the cameras that hunters use to look for wildlife, and some night vision goggles. These sources obviously work well with digital sensors which have greater sensitivity to IR than currently manufactured films. The success on film would related to how much, if any, crossover occurs between the IR filter on the light source and the combination of film sensitivity and IR filter on the camera. Unless you have a need for stealth photography, such as nocturnal animals, it would probably be a major hassle to use IR sources when conventional lights should work just as well.

jim10219 · Sep 19, 2018

Xenon bulbs, like those in most photography flash units, put out a good bit of near IR light. That's what you want. Near IR. The far IR is what those heat sensing cameras pick up. They're highly specialized and very expensive pieces of equipment. Regular IR film, like Rollei IR 400 won't come near that. Even digital cameras that are adapted to shoot IR, or "full spectrum" only pick up near IR at best.

A trick a lot of people do is to put a near IR bandpass filter over the flash or light source. That way you can get a bright flash of IR light, without producing much visible light. It's actually a good way to take photographs indoors at a crowded even where a regular flash might be distracting. You can use a couple of layers of developed, but unexposed, E-6 film as a near IR bandpass filter.

AgX · Sep 19, 2018

Ces1um said:
I could be wrong, but isn't it on the wrong end of the spectrum though? IR is around 700nm to 1mm and tungsten is like 350 to 700?

Far most of the spectral emmision of an incandescant lamp is in the IR region, plus the heat dissipated by convection. The share emmitted in the visible spectrum is just a few percent of its power intake.

Incandescant IR lamps are plain bulbs, but with a red filter coating and maybe even underrated (Tungsten wire glowing at slightly less temperature) to emit even less visible light.
The filter basically is just for the comfort of the user. For medical treatment one even could instead also use a clear halogen lamp (of course with protective glass to reduce UV radiation)...
Strictly speaking one could argue that red filter delivers an IR band especially benefitial for tissue warming.

cramej · Sep 19, 2018

anon s said:
Hello,

anyone got experience to take IR films using IR lights?

Normally I use 350-400w strobe with softbox when I take portrait with IR films (ISO 12-25) inside.
Now I am thinking my traveling gear to do the same shooting but something compact.
I am checking up Godox AD360 ... but I have just thought about IR lights.... if it works?
It might be more smaller or compact than AD360...

many thanks,

You are in need of a Sunpak 622 with IR head...

AgX · Sep 19, 2018

The Sunpak IR head is just a standard reflector-head with IR filter.
There is no IR-flash tube.

Better use a standard head and add filter that bests suits the film used.

anon s · Sep 20, 2018

hi friends, thanks for all responses ! i learnt a lot !!
the 'scientific' part will stay kind of mystery to me...
i'll play with medical red lamp but my gear on location will be standard flash and attach filter in camera.
thanks a lot !!

anon

AgX · Sep 20, 2018

"IR-Films" vary in their extention into the IR region as well as their sensitivity at the respective wavelengths. In general current films are less sensitive than IR-films from the past. In any case a precise match between the spectral sensitivity of the film and the spectral transmission of the filter (be it on light source or lens) is important.

anon s · Sep 20, 2018

the concept of IR is getting clear now thank you !

IR films using IR light

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