beginner question: tank inversions, bubbles

Discussion in 'Darkroom Equipment' started by pierods, Apr 6, 2008.

  1. pierods

    pierods Member

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    I am just starting out with a Paterson two-reel tank.

    On the instruction sheet for HP5 film, it says:

    "With spiral tanks, invert the tank four times during the first 10 seconds, then invert the tank four times again during the first 10 seconds for each further minute."

    HP5 at 400iso in ID11 1+1 is 13 minutes.

    Now, it takes 13 seconds to fill the tank. It also takes 12 seconds to fit the ill-designed rubber cap on the tank. This means that I will be starting the first inversion at time=25 seconds. Is that ok? Isn't it 25 seconds too late?

    The other option would be to pull out the reel holder in the dark, fill the tank, dump the reel holder in, start the timer and instead of doing the first inversions, rotate the agitator for 10 seconds. Then I would have 50 seconds to fit the funnel and the cap on the tank, turn the light on and do the rest of the inversions.

    Then at 12:53 I pour out the developer (it takes 7 seconds), and pour in the stop.

    Which one? Late inversions or on-time rotations?

    Question #2: after pouring some water on some test film, I see that there is a substantial amount of bubbles between the spires of the reel and on the film, and it takes three VERY firm taps to dislodge them. Is that right? Everybody says one light tap.

    What's the right thing to do?


    thanks

    piero
     
  2. Andy K

    Andy K Member

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    I start my stopwatch once all the developer is in the tank. I agitate for the first minute, and then for ten seconds each minute there after. I begin emptying the tank with 10 to 15 seconds of development time remaining, I then put in the stop bath.
     
  3. haris

    haris Guest

    I do simillar as Andy, I start my timing when developer is about half in the tank and start to pour developer out of the tank about 15 seconds before developing time expire. Regarding tapping, I learned it need one firm tap. I tap my tank once after every agitation cycle.

    Pierods, few seconds more is nothing, you don't have to be so precise and strict. If you really want to worry about things, when you start to pour in developer, bottom parts of film will start to develop before upper parts of film, as developer level raising up in tank when you pour it in. But, if you start to think that way, you will go crazy :smile:. Keep temerature of developer about 20 degrees Celsious (19 or 21 makes no difference :smile:), pour developer, start timer, start agitation, 15 seconds before developing time ends pour developer out of tank, pour in stop bath. After that, time is not that critical, even temperature, but try to keep it around 20 degrees with stop and fixer. If you can't, it is beter to have stop and fixer warmer, that is, better to have them at 25 degrees than at 16 degrees. Of course, don't overheat stop and fixer and don't use them too long, be reasonable :smile: Tap tank once after agitation cycle with every chemical you use, and that should be correct procedure to process film :smile:

    After some time, you will find out procedure which work best for you, and that will be that. Practice makes perfection, as they say :smile:

    I use Paterson and Jobo tanks. Paterson tanks fills in faster than Jobo, but not much. Putting rubber cap on Jobo tank needs only a second, Paterson takes me up to 10 seconds. Do I worry about it? NO :smile: But, if you like, buy one Jobo tank and see which tank works better for you.

    Good luck.
     
    Last edited by a moderator: Apr 6, 2008
  4. srs5694

    srs5694 Member

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    Concerning your first question, it's more important to be consistent in what you do than to follow anybody else's procedure. A little digging will uncover all sorts of different agitation techniques. None of them is wrong (but see below); it's just a matter of personal preference, how you learned, what restrictions your hardware imposes (as you've outlined), etc. Of course, if you use an agitation technique that's too far from what the manufacturer expects, you may need to adjust your development times. Also, your agitation technique can influence the final result (changing contrast, for instance). Also, agitating too much is sometimes claimed to produce surge marks, which could get too much agitation counted as "wrong," so there I go contradicting myself. :wink:

    For your second question, I typically rap my tank twice after each set of agitations, firmly but not violently. This seems to work for me. If you find you're getting air bells in your negatives (round underdeveloped areas), you've probably got problems with bubbles and should try rapping more. You'll learn best by practice. (I recommend you avoid developing irreplaceable film for your first few rolls; practice on a few expendable rolls first.)
     
  5. Woolliscroft

    Woolliscroft Member

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    I also rap twice: firmly, but obviously not enough to crack the tank.

    David.
     
  6. Andy K

    Andy K Member

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    Ps, I forgot to say, after each period of agitation I also rap the tank firmly on the counter.
     
  7. RobC

    RobC Member

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    I usually start the time immediately before pouring liquid into tank but as soon as all liquid is in tank is OK as well. Its personal preference. The important thing is consistency each time you do it. Then you can adjust time and/or agitation to get the contrast you require.

    Note that developers which give a dev time of 10 mins or more, make the influence of fill and empty times far less significant. High activity developers which give very short dev times, can make slight variations in fill and empty times much more sigificant.

    If you have a paterson tank, it may have a little device for rotating the film spools to agitate the film. That device is useless, dont use it. Inversion of the tank is required.

    I always give at least 30 seconds continuous agitation at start of dev process. For some developers more.

    When agitating I find that moving the tank upwards and then flipping the tank over and letting the developer drop to the other end of the tank works best. If you just tip the tank over, especially if only done at moderate speed or slowly, causes dev to flow through sprocket holes and can cause some streaking across your negs. At the top of the up motion, the dev becomes weightless and is easily spun over with the tank without it flowing through sprocket holes.
    Then tank is brought straight back down as dev falls down (not poured down).
    Then repeat for how ever many times you want. Two or three inversions is usually enough for each repetition every minute or every half minute for more contrast in the neg.

    Also, you must rap tank on firm base straight after agitation as the reels can slide up the spool and out of the developer. Rapping the tank causes them to slide back down to bottom of tank. Streaks along the length of the film or bubble marks on half the width of the film are an indication that film is not fully immersed in dev when at rest between inversions.
     
  8. pierods

    pierods Member

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    Thanks to everybody for all the info.
     
  9. RobC

    RobC Member

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    if you are only developing one film, still put second reel on as it stops first reel from sliding up when doing inversions. But still do rap on bench as even with two spools on, they do move a little when doing inversions.
     
  10. haris

    haris Guest

    Or, fill tank to be completely filled. I belive 1 liter of chemical is enough to completely fill the tank :smile:

    Joke :smile:
     
  11. Ronald Moravec

    Ronald Moravec Member

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    It does not matter how you time it so long as you time it same way each time. You need to find your own proper time anyway.

    Same with liquid. Use it as a two reel filling it or as a single and double filling it. Use as a single by covering the bottom with the film only. The time may be a little shorter. Use empty spacer reel.

    If you had instructions for the Patterson, they would tell you to fill the tank, then use the twist stick for the first agitation, add the final cap and invert for subsequent agitations. This works for me.

    With stainless tanks, imersing reels into the tank already filled with developer is the proper way. After that, pour in/out thru the top. With one and two reel tanks, you may pour developer thru the top, but you are asking for trouble sooner or later.

    Pattersons nicely fill from the bottom up which eliminates most all risk of uneven immersion.
     
  12. RobC

    RobC Member

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    one other tip for the paterson tank. When you put the lid on, lift one point of the edge and press center of lid down to expell some air and press lid closed. That stops it from leaking during inversions.