Any examples of Maco 820c Aura 4x5 with a Red 29

Discussion in 'Alternative Processes' started by engelfoto, Sep 4, 2007.

  1. engelfoto

    engelfoto Member

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    Anybody have any examples of the aura effect at all? Is there any? Or do you have to go to the opaque filters (89-87) in order to get the right wavelengths to create the halo effect?

    In other words, I'm wondering if visible light would cause the AURA emulsion to blow out before you got any halos, while going true IR filtration would create the right environment.

    I really want to use the film on my large format camera, but focusing is such crapshoot with IR and my old equipment that isn't perfect. I was told I only need a fraction of a mm closer to the subject and I got back the negs and they were blurry. I want to shoot wide open for the shallow depth of field, so I feel like Red 29 is the best for me. But I want that halo effect.

    What about the 70 filter?
     
  2. colrehogan

    colrehogan Member

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    You won't see the halo effect with anything less than an opaque filter with this film. You really need to go to at least an 89B. I prefer an 88A or 87. As for focusing, I just focus as normal and don't worry about any IR focus correction. What is your subject matter that you are shooting wide open?
     
  3. Roger Hicks

    Roger Hicks Member

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    Overexposure helps with the aura effect, regardless of precisely which filter you choose, but yes, you should see more aura effect with a T50 of 710nm or longer. I have however seen it with overexposed film with a filter with a T50 of only 695nm.

    710-715 nm is visually opaque at first sight but if you hold it over your eye, excluding all other light, you will see a very dim image after a few seconds.
     
  4. keithwms

    keithwms Member

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    If that film is the same or similar to Rollei 400 IR, then I can report that I haven't really seen it even with an opaque filter (#87) and substantial overexposure.

    Here are some examples of captures that were definitely on the high side of exposure, and I see basically no 'aura' or halation: 1 and 2. The edges are extremely crisp and sharp except for some motion blur. No 'glow' at all.

    Maybe I am wrong, but the 'aura' effect is simply halation, no? If that's the case then perhaps I could see it better with 220 film, these were on 120. Anyway it's still not clear to me what people mean by 'aura,' unless it is simply halation. Of course if you want halation then that can be arranged :wink:
     
  5. Roger Hicks

    Roger Hicks Member

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    Yes, it is halation, and no, I'm pretty sure it isn't the same film. Of course, the bigger the format, the more subtle the halation.
     
  6. engelfoto

    engelfoto Member

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    I don't know what T50 means but if I had to guess it would be "threshold 50" on those charts I've seen where using a particular filter will have numbers associated with various wavelengths. So, you're saying that at 695, if the number is great (or less?) than 50, I should be able to get a halo effect?
     
  7. engelfoto

    engelfoto Member

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    Yeah, it means no anti-halation layer. And that's why you don't get it with the Rollei 400. The Rollei 400 is a different film altogether from what I've read of the Maco stuff. Maco 820c I think is the same as the new Efke stuff, but Efke doesn't make the non-anti-halation "Aura" version.

    I just happened to come across a bunch of it is all.
     
  8. Roger Hicks

    Roger Hicks Member

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    Yes, T50 is the wavelength at which 50% is transmitted. As the slope is normally VERY steep, it can be taken as a convenient single reference point for IR effect. With a T50 of 695 (less than 50% transmission under this figure) you should be able to see a modest halo effect with generous exposure. It's a mixture of halation and irradiation, so it's easiest to see in bigger enlargements. But as already suggested, a T50 even a little higher at 715 will give a stronger effect, though a good deal depends on the steepness of the slope. I've not tried a B+W 093 (completely opaque visually, 87c equivalent) because the sensitization of 820c is not much above 800 nm (the 820 figure is the limit of sensitivity, not the dye sensitization preak).
     
  9. Ole

    Ole Moderator Staff Member Moderator

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    Hang on a second!

    The "wood effect" where vegetation shows up as white is wavelength-dependent, and with this film you need to filter out as much as possible of the visible light. A 695 filter does this nicely, but a 720 would be better.

    The "aura" effect is halation, and will show up on any film without some kind of anti-halation layer, at ANY wavelength! BUT: 120 film uses the backing paper as an important part of the halation control, so that will show less of it. Sheet films are big, so a 1/2mm of halo won't be easy to spot. 35mm film is best for the halo, as a 1/2mm is over 1/50 of the image height.
     
  10. engelfoto

    engelfoto Member

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    Thanks Ole, I did take this into account. I don't want a pure IR effect, I just want some of that halo, with some of that IR, even if it's a little bit. I'm looking for sharpness, but with that diffuse glow. I may not get it entirely, but I think it'll show better on the large prints on intend on making.

    This is why I was wondering if anybody has any actual pictures they can show me of a Red 29 or 70.

    I've seen the famous IR comparison chart but on that chart where they show different filters with Maco 820c, the Red filters are missing. lol... typical.
     
  11. Roger Hicks

    Roger Hicks Member

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    Dear Ole,

    True. I've generally seen halation clearest, though, with things that are highly IR-reflective against a dark background -- where, of course, the IR filter boosts contrast. I've seen this effect (which I sometimes call 'dripping with light', because that's what it looks like to me) more clearly with stronger filtration. An ordinary deep red doesn't seem to produce it as strongly.

    And I fully second your comments about enlargement, though there is a sort of 'glow' with Maco Aura even at 5x7 (the only size I have). A lot of these very subtle photographic effects, including the half-tone effect, are visible at levels at which rational analysis might suggest we should not notice them.

    Cheers,

    Roger
     
  12. keithwms

    keithwms Member

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    If I wanted halation / aura and didn't have access to films without the AH layer then I guess I would first see if I can wash off the halation layer, and then I'd also consider installing something very IR-reflective over the pressure plate in the camera. I think most pressure plates are designed not to reflect at all, but that is actually what you want for an aura effect, no? The reflection off that plate is what creates a localized aura, as opposed to wholesale fogging.

    My understanding is that the reason why we naturally associate halation with IR and not visible wavelengths is that the film bases are generally IR transmissive, hence the need for AH coating. With some film bases it could be possible to get that back reflection off the plate with somewhat shorter wavelengths as well, i.e. with an ordinary pan film.
     
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  13. engelfoto

    engelfoto Member

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    OMG, do not give me ideas man! Now I'm thinking of painting the backplate of my filmholders silver or chrome!
     
  14. Ole

    Ole Moderator Staff Member Moderator

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    You could try the usual "stupid mistake", and load the film along with the interleaf paper...

    Just make sure the paper is behind the film!

    I can't remember if the paper in these is black or white, but I do remember there are some films with white paper between the sheets. :smile:
     
  15. keithwms

    keithwms Member

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    I was thinking of popping out a pressure plate and putting it in my gold sputtering system :wink:

    If you send me your plate I'll coat it for [inserts pinky-finger into mouth] twenty dollars! No! Thirty dollars! Muahaha, I'm rich, rich!
     
  16. engelfoto

    engelfoto Member

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    Maco 820 Aura uses black paper and it's about as reflective as the back of the film holder already. But good idea! Heck, maybe I'll just find some shiny white paper and do it. Although I'd be more concerned with actual fogging as a result. The halo or "glow" is the desired affect, not increasing the overall fog, right? :wink:
     
  17. engelfoto

    engelfoto Member

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    Well don't forget I don't actually have a "pressure plate" in a 4x5 film holder. But I would think anything a bit more reflective behind the sheet would do something.
     
  18. keithwms

    keithwms Member

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    Oh if you are using 4x5 then that's easy, just put good old aluminum foil behind there, taking care to put it down smoothly.

    Aluminum Reflectance:
    [​IMG]

    Silver and gold foil would be even better.