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  1. #11
    hpulley's Avatar
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    Some film data sheets say a dark green safelight can be used at one point or other in the process but my question is: will you even be able to see the frame markers until you've fixed the film? Before fixing the film is quite opaque so there may be ghostly images on it but it will be tough to see where to cut. It isn't like paper where you can see the image fine before fixing, anyone who's had bad fixer not clear the film first time through knows it is hard to see the image until you re-fix it.

    If you expose it to light then you will fog the film that you plan to develop further so I don't think it will work anyways.

    You should really shoot entire rolls the same way. If you need to change what you are doing it is better to do a midroll rewind and load a second roll so you can process them each differently.

    Using medium format will get you less shots per roll, my 6x7 only gets 10 shots per so if I bracket two shots per scene I am only taking 5 pictures really which takes no time. Large format you can develop each shot separately!
    Harry Pulley - Visit the BLIND PRINT EXCHANGE FORUM

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  2. #12

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    Quote Originally Posted by Sirius Glass View Post
    And while you are cutting the film in half in the dark, please explain exactly how you will execute the cut without cutting an image?

    Anyway, why are your going through all this when the film is already presumably safe in the tank?

    Is what you are smoking or taking legal Down Under?

    Jus' jerkin' your chain!
    Ha.
    I was wondering what I could do if I had to switch ISO mid roll (e.g. a drastic change from 400 to 3200).
    I was hoping that after developing the roll sufficiently for the 3200 frames (because those images will be developed first, right?) I could see where to cut the roll. Then I put the undeveloped strip back into the tank for more processing to bring out the 400 frames.

    Kind of makes sense to me except for the fact light should not touch the film at all until the film is fixed.

    At this point the suggestion of an IR-vision device in total darkness is the only way to do it.

    Not that I'm going to do it. It was just an idea. It's Friday 2:00pm @ work etc. etc.

    YouTube blocked at work, but I will take a look at home (thanks 23mjm).
    Last edited by hankthetank; 01-13-2011 at 09:01 PM. Click to view previous post history. Reason: answer earlier suggestion

  3. #13
    hpulley's Avatar
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    Quote Originally Posted by hankthetank View Post
    Ha.
    I was wondering what I could do if I had to switch ISO mid roll (e.g. a drastic change from 400 to 3200).
    I was hoping that after developing the roll sufficiently for the 3200 frames (because those images will be developed first, right?) I could see where to cut the roll. Then I put the undeveloped strip back into the tank for more processing to bring out the 400 frames.

    Kind of makes sense to me except for the fact light should not touch the film at all until the film is fixed.

    At this point the suggestion of an IR-vision device in total darkness is the only way to do it.

    Not that I'm going to do it. It was just an idea. It's Friday 2:00pm @ work etc. etc.
    No, the 3200 images will be developed later! They are underexposed so will take longer in the tank.

    Not doing it is my suggestion too. You should probably process the whole thing as 1600, that'll be two stops overexposed for the shots at 400 which is OK and 1 stop underexposed for 3200. Heck, I would probably just develop the whole thing for 3200, 3 stops over is no big deal for negative film, you can deal with dense or thin negatives when you print.

    Opening the tank halfway how are you going to unload wet film to cut it? Wet emulsion is delicate... overall it sounds like a bad idea to me. Quit while you're ahead!
    Harry Pulley - Visit the BLIND PRINT EXCHANGE FORUM

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  4. #14
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    Quote Originally Posted by hankthetank View Post
    Quote Originally Posted by michaelbsc View Post
    Try this at the risk of your film, and don't blame me if it wrecks your test. But you can try using the IR goggles that paint ball shooters use.

    "Most" film isn't sensitive to IR, but I can't tell you whatever you're using won't be.
    Christ, there's something out of left field; never would have thought of that. The "night vision" head pieces worn by too-serious paintballers start at about US$260 (quick search). Then there's "how to make cheap thermal goggles" here: http://www.ehow.com/how_5625485_make...l-goggles.html

    A useful idea to try, when and if I have the time. For now I'll stick to a single ISO per roll of film.
    I got the IR goggles idea from a Kodak publication actually. That former great film company. I don't remember exactly where it was now, but there was some process they performed under IR illumination without exposing the film. Of course, they didn't use paintball toys; they had some industrial stuff.

    Makes good sense unless the film is sensitized too far into the red area. Silver Halides are UV to blue sensitive, and CMOS is IR sensitive.

    I've never tried it, but it looked pretty interesting. And you never know who might have a pair you can borrow. If you work in any kind of large place I'll bet there's half a dozen folks who have some.

    I thought the plan is to test some things, not try to squeeze multiple EVs out of a single roll.
    Michael Batchelor
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  5. #15
    2F/2F's Avatar
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    Hi,

    I know from experience that you will not ruin your film by exposing it after it has been stopped, but I have read here in APUG threads that it is not a good idea, as some change does take place.

    You cannot, however, redevelop after exposing the film to unfocused room light and expect the developer to selectively darken only the parts of the film that had been darkened prior to the room-light exposure. If you develop, stop, expose the entire roll to room light, do not fix, and then develop again, everything that has been hit by room light will darken on the negative. This will terribly fog your film if it does not completely blacken it.

    Panchromatic films will be exposed by red safelights. You can use red light to inspect your film only with a film that is not sensitive to red, such as Ilford Ortho or Efke/Adox Ortho. You can use the a red lamp at low intensity, i.e. far away from the film, if there are no light leaks around the red. Don't rely on a bare red bulb IMO, even if it is a purpose-made darkroom bulb. Get a dark red safelight filter or some rubylith to back up the bulb, as the bulbs can have inconsistencies and defects in the coatings. Paper can survive these, but film is more sensitive.

    There is one way to do what you want to do with a panchromatic film (i.e. most b/w films). Look up developing by inspection on the Web. You could try that. Don't stop the film if you do this. If you inspect, and decide you need more development, you'd have to rinse the acidic stop bath off of the film completely or it will contaminate your developer, which thrives on alkalinity.

    I think you are better off going through the standard process entirely in the dark, then intensifying your negs later if they are flat.
    Last edited by 2F/2F; 01-13-2011 at 09:32 PM. Click to view previous post history.
    2F/2F

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  6. #16
    michaelbsc's Avatar
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    Quote Originally Posted by hankthetank View Post
    I was wondering what I could do if I had to switch ISO mid roll (e.g. a drastic change from 400 to 3200).
    35mm? Or 120?

    If it is 35mm then note the frame (Write it down! Don't plan to remember it), rewind, load the other ISO film, and when you reload the first film shoot 2 frames past the point with the lens cap on. If your camera rewinds the film completely into the canister and you cannot control it, then carry a film retriever with you to pull the leader back out.

    For 120, just finish the roll. It's not that many frames unless you're shooting 645.

    Or try a two bath developer or stand develop. I've never done either of those, but lots of folks here do it all the time. Ask around.

    Quote Originally Posted by hankthetank View Post
    I was hoping that after developing the roll sufficiently for the 3200 frames (because those images will be developed first, right?) I could see where to cut the roll. Then I put the undeveloped strip back into the tank for more processing to bring out the 400 frames.

    hpully is correct. You have these backward.
    Michael Batchelor
    Industrial Informatics, Inc.
    www.industrialinformatics.com

    The camera catches light. The photographer catches life.

  7. #17
    hpulley's Avatar
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    For 120 if you have a system camera, just switch backs! Take off the 400 loaded back and put on the 3200 loaded back.
    Harry Pulley - Visit the BLIND PRINT EXCHANGE FORUM

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  8. #18

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    It should be possible, if you are careful. The film will still be sensitive to light after development and stop, but a good wash will get rid of most of the dye sensitizers in it. That means it will be mostly blue sensitive (but not entirely) and have considerably less speed than before development. If you can treat it with a chemical desensitizer at this point, so much the better. But you can probably use a deep green safelight (like Wratten No. 3) for a few seconds at least to locate the cut point and do your work. No guarantees. Be sure to let your eves adjust to darkness for at least 10 minutes before turning on the safelight.

  9. #19

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    The BTZS video posted earlier clearly shows that developed film is much less light sensitive than before development. The only question is whether if the film is further developed will it be fogged by the exposure... Anyone willing to do an experiment?

  10. #20
    Greg Davis's Avatar
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    As stated earlier, using a green Kodak #3 safelight filter for just a few seconds after most of the development is done will be fine. This will not work with T-Max film, though. It has clear warnings not to use a safelight of any color.
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