Measuring out Rodinal - How important is accuracy?

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Possibly a silly question, but...

I have a small bottle of Rodinal (well, Adonal, but the same thing) that I bought recently to try instead of DD-X. I though that, because of it's long shelf-life, it would be useful to have around.

How important are the mixing ratios when making up the developer? e.g. how much difference will a (much more easy to calculate and measure!) 1+49 mixture make instead of the stated 1+50 for instance?

I used some the other day and found myself making up weird ammounts of developer (I think it was 560ml) just so that I could have a quantity of Adonal rounded to a full millilitre. Otherwise I was getting silly amounts like 11.8ml that I can't measure accurately.

Will it make any difference, or should I just chill out? :)
 
Chill out dude... I tend to aim for the .5 mark, and aside from a contamination issue I had with my first bottle, I've never had any real problems going slightly over or under, but I do mean slightly... If it was anything important, to be honest, I'd use a different developer or be as accurate as I can be.
 
I'm a bit obsessive over things like this - keep to the required temperature to a half (Fahrenheit) degree even for black and white, keep all temperatures the same etc. However, that's mainly for consistency. There are always things you either can't control, or simply don't know.

In the case of Rodinal, it won't matter. I've used dilutions of 1 to 25, 50 and 100 and they all work. The only thing that might change if you're basing the timings on a very slightly different dilution is the contrast. And that will be affected by your agitation anyway. So, go ahead and do it.
 
There are so many other variables, was the exposure spot on, is your thermometer accurate, how long does it take you to empty and fill the tank, agitation, etc. that I always think there is a little bit of serendipity involved. I suspect that in general the various inaccuracies will average out if there is some randomness, if you are unlucky and all the variables wander off in the same direction then you are unlucky.
 
sirch said:
I always think there is a little bit of serendipity involved
Click to expand...
I lol'd at this.... If the difference between 11.8ml and 12ml was an issue for me I'd be bloody happy!!

Being a lazy arse, I never messed around with the maths and had a post-it in my dev cupboard to remind me every time. 300ml (1x35) = 6ml. 500ml (1x120) = 12ml.

I'm sure there are horrified screams somewhere, but my results were ok. I've been on HC-110(B) since January and my (new) post-it reads 10ml and 15ml. I prefer the results, but that's more to do with the developer than the precision of my developing which an optimist would probably describe as "haphazard".
 
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Same issue here. I think I need a pippette... :)
 
I think my concern stems from the small quantities used. If I’m using DD-X, then its a 1+4 ratio, so 60ml of developer for a single roll of 135. Being out by 1ml there is a relatively small variance, less than 2%. The same 1ml difference with 1+50 Rodinal is closer to a 10% variance.

Based on what’s been said though, I think I’ll just go for a 1+49 ratio as at least I can measure those volumes in the syringe I have And it will always be a rounded number.

The Adonal came in a bottle with a vinegar-bottle type top which, annoyingly, has an opening too narrow for the tip of the syringe. It means I have to shake drops of it out into a measuring cylinder instead of just drawing it into the syringe.
 
If you are really worried about accuracy I do have a 0.1 microlitre syringe though Rodinal would be a bit too sticky to move in and out.
 
My typical solution for developer is HC-110 at solution B (1:31)

That relates to 3ml dev to 93ml water.

Developing all formats of sheet film in an orbital tank can be done successfully using +/- 100ml solution.

Now HC-110 is like syrup and not easy to measure so I use an egg spoon which holds, in theory , 3ml of liquid.

The spoonful is sometimes ´just’ full , other times it clearly spills over the capacity of the spoon.
Similarly the measuring vile of 100ml used will have anything from 93 -100ml of water in it prior to adding the developer. I rarely ready the water level !

The expected expected and usually decent results are obtained every time.

I don’t do clinical accuracy ..... as mentioned above there are too many other variables to make exact science in the ‘darkroom’ necessary imo.

Mix somewhere close, wing it and have fun....... I’m sure you’ll get pleasing negs (assuming all other areas , shutter speed etc , ) have been executed fairly accurately.
 
Asha said:
Now HC-110 is like syrup and not easy to measure so I use an egg spoon which holds, in theory , 3ml of liquid.
Click to expand...

For 9ml I use a syringe, for 16ml I have a marked-up 35ml film holder
:geek:
 
Hc110 is a syrup, Rodinal is a normal liquid.
 
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