What is the "AURA" effect with IR film?

[sanking]

I bought some 4X5 Rollei 400 IR film from Freestyle Sales. On the package there are instructions for development, and a note, "AURA" effect by overexposing.

Sadly, I never heard of the AURA effect. Can someone explain what it is?

Sandy King

[Vaughn]

My guess (and only judging from Kodak's B&W IR film), is that the lack of an anti-halation layer allows for some light in the brightest areas to pass thru the film and then expose it again as the light reflects off of the pressure plate (or film holder on LF cameras) of the camera. Hence the "arua" around the highlights. This why 35mm cameras with patterns on the pressure plate did not work all that well with IR film...the light would bounce off the pressure plate unevenly.

I noticed the same effect with x-ray film in LF cameras(again. no anti-halation layer).

Vaughn

[Brian C. Miller]

Vaughn is correct, the "aura" effect comes from the lack of an anti-halation layer. I never saw the patterns from the pressure plate myself, though.

The halation is most significant on 35mm size film. You will not (of course) get the same area of halation using larger formats. It will look minimal on 120, and almost nonexistant on 4x5. The most halo-ed film was Kodak HIE, RIP.

The minimum filter for this product is Red 29 (B+W 091). I use B+W 092, and Hoya 720 has the same effect. Past that, the film really isn't especially sensitive, and the exposure must be significantly increased. Bracket at ISO 50, and go from there.

[Vaughn]

Vaughn is correct, the "aura" effect comes from the lack of an anti-halation layer. I never saw the patterns from the pressure plate myself, though.

The halation is most significant on 35mm size film. You will not (of course) get the same area of halation using larger formats. It will look minimal on 120, and almost nonexistant on 4x5. The most halo-ed film was Kodak HIE, RIP.


The pressure plate info came from a fellow here at the university who found he had to tape a smooth piece of paper over his pressure plate to avoid the pattern. I have not used IR in 35mm myself.

Is the halation differences in format sizes just due to the enlargement factor? I got some pretty substantial halation on 7x17 using x-ray film.

Vaughn

[Peter Gomena]

Try putting a piece of white paper behind the film. You'll get plenty of aura then!

Peter Gomena

[sanking]

The minimum filter for this product is Red 29 (B+W 091). I use B+W 092, and Hoya 720 has the same effect. Past that, the film really isn't especially sensitive, and the exposure must be significantly increased. Bracket at ISO 50, and go from there.

First, thanks to all for the responses about AURA. That certainly makes sense.

So the film is ASA 400 but only for exposure to visual light? For full IR look you have to use a 92 or 720 filter and increase exposure? I have found this to be aboutr +5 stops for the Ilford SFX. Would that be about right for the Rollei 400 IR with a 92 or 720 filter?

Sandy

[Jim Edmond]

I've just run a roll of IR400 (35mm) with a Hoya R72. 5 stops compensation seems to be correct.

[Brian C. Miller]

Is the halation differences in format sizes just due to the enlargement factor? I got some pretty substantial halation on 7x17 using x-ray film.

YMMV, caveat emptor, everybody uses the stuff differently. ;) Yes, the halo remains the same, but the enlargement is what makes the difference. Of course, a film with an anti-halation layer, like Konica or Ilford SFX or whatever, will have about half the halo. It is also quite easy to expose the film and get good results without exposing for the halo. I have heard other people talk about getting a pressure plate pattern, but I always shot HIE without the sun in the frame, and I didn't expose for radical halation.


So the film is ASA 400 but only for exposure to visual light? For full IR look you have to use a 92 or 720 filter and increase exposure? I have found this to be aboutr +5 stops for the Ilford SFX. Would that be about right for the Rollei 400 IR with a 92 or 720 filter?

Yes, Kodak HIE was the only film that was equally sensitive throughout its entire range. EI 12 sounds about right. However, I can't see or meter in IR so exposure is tricky. One time I was completely in the shade among evergreens, and what I didn't know is that the area was chock full of IR light. The N frame was actually N+1, and my N+2 shots and above were nearly bulletproof. The evergreens looked awesome, though, as good as a deciduous canopy.

One of the things that I really like about HIE is its extended IR sensitivity, so that all the vegetation reflects IR, not just deciduous-type plants. (I don't miss it yet because I have a freezer full) The best images for IR films will come from grass and deciduous trees. Evergreens will range from grey to black, depending on the species. You will have to experiment.

What will be reliable is that everything will look crystaline clear. No haze! I have a photo of a mountain (Mt. Hozomeen) from over 25 miles away, and it is absolutely clear.

[rguinter]

Sandy:

These on HSI 4x5-inch.

I don't know if the blooming effect is significant with 4x5-inch but I sense it is (somewhat) in the highlights.

Your opinion is welcome.

Bob G.

[rguinter]

...The minimum filter for this product is Red 29 (B+W 091). I use B+W 092, and Hoya 720 has the same effect. Past that, the film really isn't especially sensitive, and the exposure must be significantly increased. Bracket at ISO 50, and go from there.

I have quite a bit of this in 120-size that was custom cut from the equivalent Aerochrome.

I shoot it in my Fuji 645 with a red-grad over a Y2 and the effect is quite nice shooting at ASA 50.

See my photo 4, post # 7 in this thread:

http://www.largeformatphotography.info/forum/showthread.php?t=68794

Bob G.

[rguinter]

Yes, Kodak HIE was the only film that was equally sensitive throughout its entire range. EI 12 sounds about right. However, I can't see or meter in IR so exposure is tricky. One time I was completely in the shade among evergreens, and what I didn't know is that the area was chock full of IR light.

Yes I'm seeing the same thing... deep shadows sometimes chock full of infrared. Much more than expected.

Example attached on Efke Aura. f22 @ 30sec w/B&W 092

Bob G.

[Vaughn]

Bob, what I thought as the aura can be seen around the sculpture figure.

I also thought of an alternative source of the Aura -- a complete guess, but can any of the aura be generated due to the different refractive factors (proper term?) glass has for visible light and for IR? In other words can the aura be partly due to a "ghost" image caused by the visible light bending slightly differently than the IR?

To answer my own question now that I took the time to type it out, is probably no. 1) the arua is still probably there even when a filter is used to block out all the visible light, and 2) the amount of "ghosting" (off-setting of the image) would probably increase as one leaves the center of the image - and that does not seem to be the case in IR images I have seen...thus probably no ghosting.

Vaughn

[rguinter]

Vaughn:

Yes, your eyes are better than mine.

When I go back to the photoshop file and enlarge I see the aura completely around the figure.

Section crop attached.

Bob

[Cor]

I once beta tested the than MACO AURA versus the "standard" MACO 820IR (aka EFKE) in 4*5.

I could not get an anti-halo effect as we know it from the late Kodak HIE films. I tried aluminium foil, white paper and even glass behind the AURA film; no effect whatsoever.

Only overexposure yielded some aura/halo effect, but than printing became very though..

Best,

Cor

[IanG]

EFKE make two versions of their IR 820 films the original has an anti-halation layer but it doesn't give the same effects as Kodak's old IR films, so they now also make "Aura" with no anti-halation layer.

So it's purely down to halation.

Ian

[Vaughn]

Vaughn:

Yes, your eyes are better than mine.

When I go back to the photoshop file and enlarge I see the aura completely around the figure.

Section crop attached.

Bob

It is also evident in the waterfall image -- either rock or log is glowing in the lower middle of the image. Most evident where there is a sharp border between light and dark, though its effect probably is all over to a certain extent.

[tgtaylor]

FWIW, I have had good success shooting the Rollie product in both 120 and 4x5 using a Cokin 007 IR filter allowing 6 stops for the filter (i.e., ISO 6). The Cokin literature says to allow 6 stops for the filter and my spot meter confirmns that.

[rguinter]

Vaughn:

I actually didn't like the waterfall image very much... probably on account of the aura effect. I mentally told myself when I do it again I would try IR-820 non-aura film.

I'm planning to do it again in winter (maybe soon now that winter is actually here). It is about 90-minutes drive north from where I live. Raymondskill falls. To get the shot one has to wade out and set up on a ledge just a few feet from the second (steeper) part of the falls so it's a treacherous spot. And I'm not as young and fearless as I once was.

But maybe soon I'll have a better shot of it. Hoping anyway.

Cheers. Bob G.

[sanking]

Vaughn:

I actually didn't like the waterfall image very much... probably on account of the aura effect. I mentally told myself when I do it again I would try IR-820 non-aura film.

I'm planning to do it again in winter (maybe soon now that winter is actually here). It is about 90-minutes drive north from where I live. Raymondskill falls. To get the shot one has to wade out and set up on a ledge just a few feet from the second (steeper) part of the falls so it's a treacherous spot. And I'm not as young and fearless as I once was.

But maybe soon I'll have a better shot of it. Hoping anyway.

Cheers. Bob G.

Bob,

Thanks for posting the images showing AURA effect. I actually don't like it all that much either so I will be exposing the Rollei 400 IR normally in order to minimize the effect.

BTW, any anyone compared the grain of Rollei 400 IR with Ilford SFX? I did some work with SFX in the fall during my trip to China and on a recent visit to Ossabaw Isalnd off the coast of Savannah and my conclusion is that for any print size over 11X14" the grain from SFX (roll film in 6X7 and 6X9 formats) is simply too much for my taste. Can I expect about the same from Rollei 400 IR?

BTW, I have been using a digital camera converted to IR to evaluate exposure for film. It is pretty effective and will definitely give more accurate exposure than a regular light meter reading.

Sandy

[Ron Marshall]

Some IR comparisons:

http://www.digitaltruth.com/products/product_tests2/index.php

[sanking]

Some IR comparisons:

http://www.digitaltruth.com/products/product_tests2/index.php

Wow, great link. But quite surprised to see a film comparison on a digital site?

Sandy

[Vaughn]

Vaughn:
...To get the shot one has to wade out and set up on a ledge just a few feet from the second (steeper) part of the falls so it's a treacherous spot. And I'm not as young and fearless as I once was.

Cheers. Bob G.

Take care! Don't let your obit read "He died doing a re-shoot."

Near-by hikers found Bob floating below Raymondskill Falls. His last words were, "How's that aura, Dora?" Friends and family are confused as his wife's name is not Dora and Bob was not a known Zappa fan.

His relatives were able recover Bob's film holders downstream. His last image he made before he plunged over Raymondskill Falls was unharmed and it was developed. Generally, the family felt he did a better job the first time.

Vaughn

[Ron Marshall]

Wow, great link. But quite surprised to see a film comparison on a digital site?

Sandy

Their name never made sense to me as they sell mostly photo products.

They host The Massive Development Chart.



http://www.digitaltruth.com/

[Kirk Keyes]

EFKE make two versions of their IR 820 films the original has an anti-halation layer but it doesn't give the same effects as Kodak's old IR films, so they now also make "Aura" with no anti-halation layer.

So it's purely down to halation.

Ian

Another source could be from IR's ability to 'see' more deeply into the surface of a subject. Skin is fairly transparent in IR, as you may notice from how blood veins are rendered. So some subject surfaces are rendered a little softer.

But mostly, it's going to be the halation.

[Jim Michael]

The 120 rolls of the non-AH version we processed had a large number of emulsion defects. Using the dust & scratch filter with the threshold set to something like 32 saved a lot of retouching time.

Don't mistake that 820 for a film speed. :)



EFKE make two versions of their IR 820 films the original has an anti-halation layer but it doesn't give the same effects as Kodak's old IR films, so they now also make "Aura" with no anti-halation layer.

So it's purely down to halation.

Ian

[davemiller]

The flaring effect is much more evident in the smaller formats due to due to the greater degree of enlargement generally employed.

[rguinter]

Take care! Don't let your obit read "He died doing a re-shoot."

Near-by hikers found Bob floating below Raymondskill Falls. His last words were, "How's that aura, Dora?" Friends and family are confused as his wife's name is not Dora and Bob was not a known Zappa fan.

His relatives were able recover Bob's film holders downstream. His last image he made before he plunged over Raymondskill Falls was unharmed and it was developed. Generally, the family felt he did a better job the first time.

Vaughn

Yeah... but gotta get that winter shot with all the ice floes. Live dangerously... that's my motto.

Bob G.

[rguinter]

I looked through my summer 2010 photos and found a few more... these done with Efke Aura.

Typical exposures around f16 @ 1sec w/ B&W 092 filter.

The truck f22 @ 4 sec w/ B&W 092.

Cheers. Bob G.

[Brian C. Miller]

The first one demonstrates the reflection of sunlight. Note how the sun reflected off the cross produces a halo. The second one shows some halation from the willow tree. The crop is from the branches on the left. The lack of a halation layer allows the light to bleed, creating a halo. I would not expose the film this way on LF, as I'd rather just get the "wood" effect and have everything ultra crisp.

Kodak HIE, 35mm, Nikon FTN, 50mm lens, 092 filter.

[Thalmees]

FWIW, I have had good success shooting the Rollie product in both 120 and 4x5 using a Cokin 007 IR filter allowing 6 stops for the filter (i.e., ISO 6). The Cokin literature says to allow 6 stops for the filter and my spot meter confirmns that.
A good reference point here tgtaylor.
Thanks.