Rodinal 1:50 By Weight

[Pieter12]

Plus a scale is something that can get dirty son collect dust and chemicals, takes up more space in the darkroom, go out of calibration, etc. I small graduated cylinder is not that hard to us

So one 35mm film in stand development requires a litre of solution. Does this mean that if you want to do say, 3 x135 films at once you need a 3L tank? Is there a Agfa Rodinal source for this that you can refer me to?

Thanks

pentaxuser

I cannot locate the Agfa data sheet where I had read that info. Adox states to use at least 5ml per roll of film, 5ml for 4 sheets of 4x5.

 

[pentaxuser]

I cannot locate the Agfa data sheet where I had read that info. Adox states to use at least 5ml per roll of film, 5ml for 4 sheets of 4x5.
View attachment 266733

Thanks, I Iooked at my old Agfa Rodinal(the genuine Agfa Rodinal ) sheet and could find no mention of any min quantity but Ed Buffalo in his article "Appreciating Rodinal" does actually say that Agfa's recommendation is min 10ml but doesn't give a source for this However he goes on to say that he has found that 5ml is fine as Adox states

Mind you, the same Agfa instructions that I have state that once opened a bottle is good for at least 6 months. Now if that is not an understatement, I don't know what is I used my Rodinal the other week and from opening it has lasted now about 196 months

pentaxuser

 

[john_s]

From an Agfa pdf on film developers (1999):

"Yield
One-shot developer.
With 500 ml concentrate about fifty films (135-36 or 120 rollfilm)
can be developed."

which could be read to mean 10mL per film.

And yes, I know that less also works.

 

[Murray Kelly]

Scales that will accurately measure 500g to even as good as 1% are pricey. I'd fill it to 500 as best you can, suck out 10ml with a syringe, discard that and suck up the 10ml of Rodinal and mix. Normal usage is for 1+49.
Measuring exactly 500g (ml) is your problem not the Rodinal.

 

[RoboRepublic]

First, it is 1+50, not 1:50 and I believe Agfa recommended a minimum of 10ml for each roll of film being developed.

For my edification, could you please help me understand the difference between the '+' and the ':' ?

Back to the point of the original post, the most effective way I can see to simplify and streamline the darkroom process (at least in terms of diluting your developer) with a Rodinal derivative is to premeasure the Rodinal(-derived) developer concentrate. You'll want a bunch of tiny vials for your 10ml and 2.9 ml concentrate doses, and I can't vouch for the longevity of a Rodinal clone once decanted from the original bottle over the original crystals (of sulfite?).

When it's time to process, fill your mixing beaker to the appropriate line (290 ml or 500 ml) and pour in the contents of the appropriate size concentrate vial. Stir, and ready to process. As I noted previously, this is plenty precise unless you're fanatical about your sensitometry and print only graded paper (and can get only #3).

For most of the rest of us, it's sufficient to have a 10ml syringe graduated in 0.1 ml -- pour concentrate into a small beaker, draw up the necessary amount, pour the rest back into the original bottle, squirt the measured liquid into the mixing beaker, rinse the syringe with the beaker contents, close up the concentrate bottle, stir, and ready to process. A pair of marks on your mixing beaker will suffice to eliminate a large graduated cylinder. With some brands of Rodinal clone, you can draw directly from the concentrate bottle with the correct size syringe, and eliminate a second graduate. And now you don't need to mess with a scale.

Donald, interesting idea to decant into smaller vials; I'm not sure why I'm so resistant to syringes. Possibly because its one more item that needs thorough cleaning. I'll get a highquality one and see if my experience over last time (using a 200ml syringe for ddx 1:4/1+4) is better.

Over the years I've tried just about everything to measure small amounts of Rodinal. This 10mm dropper is the best I've found so far:
CLICK HERE
Brian P

Thanks Brian, I'll give this a shot.

If I understand correctly, it is the volume of the water that is the issue - he wants to make up the Rodinal without using his 500mL volumetric flask - or any other measure of volume once he knows the equivalent weights.

Sort of, measuring out 490ml using a volumetric flask, then measuring out 10ml using a syringe, or a skinny flask, is one more item in the dark room. The rodinal is especially a pain, since the quantity is very small.

But the water has to go into something, even if it's the film-developing tank. Easy enough to once figure out where the 500ml level on the film developing tank is and mark it (with a scratch or something) and then just add Rodinal concentrate with a syringe to that. Likely, though, he's mixing in something and pouring it into the tank, which makes the whole idea of weighing out everything a little more complicated than necessary I'd think.

Best,

Doremus

Doremus, you have the right idea; However to use the daylight tank as mixing vessel would mean, chiefly, that I cannot load it with film in my dark bag The idea is to be precise, and convenient in space. A scratch would work, but in knowing myself I'd be paranoid that I over shot or undershot the scratch mark, much the same way as I try and read the meniscus on a beaker.

 

[MattKing]

For my edification, could you please help me understand the difference between the '+' and the ':' ?

Historically, Kodak frequently used 1:49 in the same way as I and many others use 1+49.
Many chemists will tell you that Kodak should have used 1:50 instead (1 part amongst 50 in total).
It becomes more strange when you see something like 1:1 in a Kodak document.
There are heated arguments about this in a number of places here and otherwise on the internet.

 

[RoboRepublic]

Over the years I've tried just about everything to measure small amounts of Rodinal. This 10mm dropper is the best I've found so far:

CLICK HERE

Brian P

Small update: measuring with this, I found rodinal 10ml to be 12g.