Rodinal Virgin - Be Gentle

Discussion in 'Film and Processing' started by stuart_pratt, Aug 13, 2018.

  1. Following recent strange blobs on my negs, in addition to the detective work necessary to resolve that problem (see thread here - Emulsion defect? ), I have decided to give Rodinal a go (more specifically, Tetenal’s Paranol S).

    I’m wondering how people generally measure the small volumes of developer to any accuracy, and assume that most people must use a pipette, when dealing with 1:50 or dilutions beyond that. I’m not interested in doing stand development at homeopathic dilutions, so would probably use the 1+25 or 1+50 dilutions, which gives between 10 and 20ml of developer per shot, at my normal 500ml tank volume. I thought I could weigh it instead, as I have a balance which will do to the nearest 10th of a mg, and I’ve found the density from a COSSH datasheet sourced online (1.386 for anyone that is interested).

    Anyone else do this, or can think of any reason this wouldn’t be a good idea?

    I have assumed the acceleration due to gravity in SE England is close enough to 9.81 to not worry about, and that any variations in density due to ambient temperature can be ignored (that’s a joke, for fear of starting a whole new topic)!

    I'll be using mostly Kentmere 100 and FP4 in 35mm and FP4 or HP5 in MF, so any advice on these combo's greatfully received.
  2. These are what I use

    Measures 2a.jpg
  3. I haven't used it with Rodinal, but I have a 10ml graduated cylinder with 0.2ml divisions.

    I think I got that one in my college years when I was doing E6 with the Unicolor liquid concentrate kits.
    Actually, though, I think the E6 kits are big enough to use 1ml divisions for most of the chemicals, but maybe one needed the 0.2ml.

    Weighing would be better, as that avoids any thermal expansion effects, though normally the temperature should be close enough to development temperature not to be a problem.

    The syringe shown above only has 0.5ml divisions.
  4. Honestly, 10-20mL is a pretty decent sized volume to deal with, and I also use a 10mL graduated cylinder.

    A pipette would, IMO, be unnecessarily cumbersome especially when you don't need that level of accuracy or precision(I say that as an analytical chemist-I use pipettes when needed, but avoid them if not).

    Also, even if you DID need to be that exact in measuring developer, your typical volumetric or graduated transfer pipette is calibrated "to deliver"(T.D.) liquids with a viscosity similar to that of water. Remember that when used properly, a glass pipette should be allowed to drain under gravity, and the calibration accounts for the amount of liquid remaining in the tip. Pipetting a "syrupy" liquid like a developer concentrate will throw this off, although of course if used properly it should at least deliver precisely(just not necessarily accurately).
  5. Overkill.As long as you are consistent with your measurement, time will compensate for any inacuracy in measurement. Thats why we take notes. :)
    Ray House and wogears like this.
  6. Here is my heresy on Rodinal. Forget the ratios TOTALY! For ages I have used just 3ml of Rodinol in my 450ml Nikor tanks, @ 16 min. 3 min pre-soak with DI water. Agitation has been 9 EZ over & up's the first minute, with one (1) EZ over & up on the minute marks. Two (2) water stop bath rinses, plain thiosulfate hypo for 2x film clearing time. This 3 ml is for a 120 or 135-36 roll. Same time for most b/w films. I measure the Rodinol with a 5ml cough syrup bulb available at most chemist/pharmacies. Bill
    stuart_pratt likes this.
  7. Dustin McAmera

    Dustin McAmera Yorkshire, mostly on film.

    Are we talking about the same Rodinal? Mine isn't thick; I would characterise it as perfect for pipetting. It's even coloured to help us see the surface. Try pipetting HC110; it's like treacle, and you have to take considerable time and care to empty and wash the concentrate out of your pipette (or whatever). I have no idea how Kodak meant you to dose it, but I like it enough to forgive them.

    I don't think it hurts to be precise where you can. I use a graduated glass pipette with a syringe-type pipette-filler. It does 0-10 ml in 0.1 ml steps, I think. It's no harder or slower than pouring into a small measuring cylinder, and the scope for spillage is much smaller, since you don't lift the open bottle off the table. I got a half-full box of pipettes from a skip at the lab where I used to work (science lab, not photographic); probably harder to get than a cylinder, from common photo equipment suppliers. I mean to keep using them until I break the last one, or until the last unbroken ones are put with me into my pyramid. I would always choose a pipette over a syringe.
    stuart_pratt likes this.
  8. Thanks for replies. I cooked the first roll today, in Paranol S. Whilst I appreciate that the accuracy weighing brings probably isn't warranted, it was so easy just to set the cylinder on the scales, zero, add 13.6g (10ml) of developer, top up to 500g with water. BYU.

    They look a bit contrasty, but I'm used to pretty low contrast 2 bath negs for my condenser enlarger so I may have to adjust. We'll see how they print (when they dry!).

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