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  1. #21
    georg16nik's Avatar
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    Quote Originally Posted by matt nalley View Post
    In that case I think I'll push it to 10 minutes in the 1+13.5 dilution for the 2nd roll.....
    Telescope. 2000mm effective focal length, fixed at f/10. I've also been using a #12 yellow filter. That probably takes away 1/3 (?) stop. My early attempts were very low contrast, probably due to film choice, so I added the filter and got so used to it I forget it's there (despite seeing a yellow moon in my viewfinder). I didn't even think that it may be unnecessary with ATP until now. Is there any chance the filter in combination with ATP is a bigger problem than my development method in terms of reducing EI? It certainly didn't have more than the expected 1/3-1/2 stop impact on films I've used before (mostly Delta 100, FP4, Pan F).
    Matt, how long exposures were the last ones?
    ATP might run into some reciprocity failure above 1 second, so it might need an extra 1/3 stop (or more) to compensate for that..

  2. #22

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    Quote Originally Posted by georg16nik View Post
    Matt, how long exposures were the last ones?
    ATP might run into some reciprocity failure above 1 second, so it might need an extra 1/3 stop (or more) to compensate for that..
    Definitely nothing that long, georg16nik. I usually bracket at and slower than 1/ISO. The first roll of ATP was bracketed as follows: 1/30s, 1/15s, 1/8s, and the hat trick. The 1/30 and 1/15 frames are definitely underexposed (or underdeveloped), and the 1/8 frames are either perfect or slightly underexposed, too. The hat trick frames probably range from 1/2 to 1/8. When I get back into a dark room next week I can make test prints to determine which exposures are closest to ideal. I'm not great at reading negatives, but compared to my best frames from a roll of FP4 (even those were slightly underexposed) it looks like 1/8 on this roll of ATP is nearly identical.

    The second, still undeveloped roll was shot at 1/8s, 1/4s, and the hat trick.

    The "hat" trick is used in astrophotography for long exposures. To avoid vibrations from the camera shutter a hat or black cardboard covers the lens/telescope (without touching it of course), you engage the shutter at bulb, wait a few seconds while everything settles, then move the hat or board and time the exposure. Repeat at the end. It's really easy for exposure times that can be counted in seconds or minutes, but at less than 1 second it's a little tougher.

    For slower films I needed to add this exposure method because anything longer than 1/250s was capturing shutter vibration as ghosting, for lack of a better work. The film plane shutter is horizontal, so those negatives almost looked like double exposures with one moon slightly to the left of the other. Strangely though, at least in this roll, I'm not seeing that effect at much slower speeds. Either that or it's so subtle that it manifests as slightly out of focus, soft edges.


    ...looking back at my original post I think my estimated EI is fast.
    Last edited by matt nalley; 08-20-2011 at 08:55 AM. Click to view previous post history.

  3. #23
    georg16nik's Avatar
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    It will be interesting to see some astro shots on ATP!
    That film gives a lot of room, to play with filters etc etc.

  4. #24
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    Quote Originally Posted by matt nalley View Post
    Thanks for the tips, Athiril. By halo I assume you mean an undesirable exaggeration of the sharp edge effect Rodinal can produce, particularly with stand development, which is why you advise more frequent agitation. Correct?
    I mean something you'd see on a bad HDR, it's more than a mere exaggeration.

    Here is an altered contrast example;


    Also lenses with bad vignetting become terrible. Eg; even the Olympus Zuiko 28mm stopped down... the vignetting becomes a crop.


  5. #25
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    Quote Originally Posted by Athiril View Post
    I mean something you'd see on a bad HDR,
    Here is an altered contrast example;
    Good examples , the picket fence as it gets further away, by the two windows, really shows the undesired effect.

    BTW: Is there any good HDR?
    D-76 is a standard developer, although not one I use.
    Ansel Adams - The Negative

  6. #26

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    Quote Originally Posted by georg16nik View Post
    It will be interesting to see some astro shots on ATP!
    That film gives a lot of room, to play with filters etc etc.
    My next project is a deep sky object...if I ever finish this one

  7. #27

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    Athiril, yep, that looks awful. It's even bad around the leaves. Was that Rodinal stand development or agitation every 2nd minute?

    I like the sidewalk photo. You don't need to crop very much to remove the vignetting. I don't see any halo effect.

  8. #28

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    Quote Originally Posted by trexx View Post
    BTW: Is there any good HDR?
    To answer that rhetorical question: no.

  9. #29

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    In terms of development, treat it like Kodak Tech. Panchromatic. It is a bit faster, but it is a similar type of film.

    I have tried several things to tame the contrast, and the only one that really kills it enough to give me mostly normal negs is POTA.

    The data sheet is worth a read, though it says nothing about POTA to my recollection.

    I use the POTA formula in The Darkroom Cookbook for five to seven minutes (six for normal contrast, five for a little less, and seven for a little more). I expose at EI 3.

    With a working EI that low in order to get normal-contrast negs, there is a trade off. The benefits in resolution and sharpness over a more standard film have to be balanced by the fact that you likely need to use wide apertures and/or long exposures (i.e. a tripod).

    Personally, while I think this film is to die for on a technical level, in most cases T-Max 100 is a more practical choice. The sharpness and resolution benefits of the ATP over T-Max won't be seen until you start enlarging your prints to a notable degree. There are differences in tonality, though.

  10. #30

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    Thanks, 2F/2F. I have only a vague idea of what a lot of that means, but it sounds like valuable information. I'll definitely read about POTA and add it to my list of potential developers for ATP. As for the practicality of other films, I agree, but my goal is a 16x20 or bigger enlargement from 35mm. So far none of the "very fine grain" films I've tried could produce what I would consider a quality print at that size. If I had several thousand dollars to buy a much bigger telescope and a medium format camera, then I could probably get away with something like T-Max.

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