Need to pick people's brains, does snow Reflect IR light? EIR film

[jm94]

Hi guys! Britain is braced for loads and loads of snow, starting tomorrow. Now i fancy taking a roll of EIR out of the freezer and using a few exposures, cutting the used strip away in the dark to develop, and placing the film back in the freezer. However I am having trouble finding out if snow reflects IR light as it does all visible light, or if it absorbs some or all IR light. The films sensitivity seems, according to kodak peak around 750nm and roll off towards 900nm giving me 680??? - 900nm leeway. I can find very little on the internet that gives me a conclusive answer, and do not want to defrost a roll of EIR if i am wasting my time. Got a roll of velvia, delta 100 and ektachrome 100D (and a Hi8 camera, one with the biggest and sharpest lens on any videocamera i have had, was given to me and cannot afford a high end camcorder but that gives a great picture with professional grade ME tapes and does not pixelate on a large TV like most digitals below a high price range and has all the manual exposure, mic sound source, and focus controls), all ready as me and a couple of friends are going to be taking many pictures of Bath in the snow, as i have never seen bath covered in snow, we are going to make a shoot of all the mayhem that will ensue and a snow covered bath. i plan to go to high points, i know a few great ones, one of which nearly got me into a spot of bother yesterday as i found the spot. And i want to get photos of key areas around Bath using the EIR and Velvia and B/W. I will be using an orange filter for the EIR and will bracket, and will process it as soon as I return home in E6. Have never used EIR, i had planned to shoot some of one of the rolls during my last family visit, but they didn't arrive in time! I know it has to be loaded/unloaded in darkness though! And will be switching off all heating before loading it into a tank.

But the £1+ a shot question, does snow reflect or absorb any, some, most or all IR light? As if it does like it does visible light, then its worth it, if it absorbs IR light, it will be a waste of money and film.

Any help will be great!

Jacob

 

[pdeeh]

(there was a url link here which no longer exists)

 

[ath]

Yes, it does reflect. Should be nearly 100% as for visible light.

 

[jm94]

The reason i asked and what AgX said in the topic you linked to (sorry i hadn't found that) Is water is a good absorber of IR light in liquid form. From what he said and from how snow crystals vary and thickness of the snow as well, it seems there are many variables.

 

[pdeeh]

perhaps if you get lots of dry powder snow up there in BANES, it'll work ?

 

[ath]

IR has a very broad range, including heat. Water is used to absorb this IR radiation.
"IR" in photography is only a very narrow range directly below the visible range. Except from the fact that we (and as a consequence to this all normal colour films) cannot see this radiation it behaves more or less the same as visible light.

Snow flakes have a very fine structure which scatters back light. This is basically the same effect as the wood effect. Chlorophyll is transparent to IR and the foilage structure scatters back the IR light which makes it look "white". Chlorophyll is missing in snow which is the reason why it looks white in the visible range as well.

 

[AgX]

Basically IR-radiation is

-) absorbed by solid water

-) passes haze

-) is reflected from greater droplets (clouds)

-) is reflected from crystals (snow)

 

[jm94]

Cheers for your help guys, I will be giving this a shot! I am looking forward to seeing how the pics will turn out!

 

[mooseontheloose]

I've shot EIR in the snow but haven't processed it yet (!) -- here's an image with a lot of snow I did on HIE: (there was a url link here which no longer exists). I'm interested in seeing how your images turn out!

 

[jm94]

Have shot an entire roll, there was so much to shoot with IR around bath and the canal! Will process it later! I did many shots i hope are good pieces of art, stay tuned guys i will scan them once processed! Also shot a roll of velvia, and 100D super 8, but my B/W roll got botched, the camera jammed! Who knows i might get addicted to EIR and want more, at 30+ pounds a roll :O

 

[Steve Smith]

That's a good question and one I don't know the answer to.

The last time it snowed here, I used some Ilford SFX film but without the IR filter - just because it's all I had.

Some of them in my gallery. This is my favourite:




Steve.

 

[mooseontheloose]

Nice image Steve! One of my goals this year is to play more with SFX -- I never really seriously considered it before when there were more infrared options, but it seems like there aren't that many choices left.

 

[jm94]

I processed the roll, first of all do not waste a roll of EIR on snow in future guys, it was a waste! Only plants and people in coats other than black that did not have snow on them showed up red, the snow was, painfully, white. I did bracket. Got a few good IR shots, one from atop a high building with everybody in the town centre showing up as red, that is about it. A pointless waste of a roll it seems, but it shows the batch is good and the seller has more, so i am going to nab a couple more.

So that has answered the question if it is worth using EIR on snow... no :O

 

[AgX]

That does not contradict what basically had been saif about IR reflection.

First, with EIR one typically uses a mild filtration, thus the snow will reflect a lot of light, including visible, to the film.
Second, even with a strong filtration, as in most b&w IR-photography, a chromogenic IR-reversal film exposed beyond a limit will show white.

 

[jm94]

Hmm that could be it, a shame mind but i will take some more once the snow has melted of the same scenes Water Absorbs IR light as we know and there is a tree overhanging a lake, red tree and green reflection in the water might be a good shot, among a few others! Seems that using IR film, especially EIR/Aerochrome seems to be a learning curve upon itself, and from what i saw from bracketing, the exposure latitude of EIR is more narrow than most other slide films it seems.I used a hoya orange filter, gave me the colour balance i wanted from EIR.