Dumb Rodinal Question(s)

[wjlapier]

I have several bottles of Rodinal and I'm running out of Kodak D76 ( one pouch left ). I can mix the Kodak just fine with a gallon of water. But, my brain can't figure out how to mix Rodinal to make 1 gallon ( or so ) developer. I go through it pretty quickly, so I'd prefer to make a gallon batch. One shot is what I'm looking for at full strength.

Thanks again!

 

[Wayne]

Ehhh, for full strength you need a gallon of Rodinal.

Hint: That's not what you want.

 

[Wayne]

For one gallon of 1:50 use 2.56 oz of Rodinal

 

[Wayne]

and don't fret about the 6

 

[MattKing]

For one gallon of 1:50 use 2.56 oz of Rodinal

Is that an imperial gallon, or a US one?
What dilution were you aiming for?
There are ~3,785 ml in a US gallon.

 

[Wayne]

Is that an imperial gallon, or a US one?
What dilution were you aiming for?
There are ~3,785 ml in a US gallon.

s/he's in the usa so there are no Imperial gallons.

 

[mrosenlof]

Rodinal doesn't keep well once dilluted, so only mix that gallon if you plan to use it all right away.

 

[Donald Qualls]

Rodinal doesn't keep well once dilluted, so only mix that gallon if you plan to use it all right away.

Bingo! The 2.5(6) ounces of concentrate per US gallon is the right ratio for 1:50 (or twice that for 1:25), but only mix what you'll use within the next few hours. Mix in the morning, and develop sixteen single rolls of 120, should be fine. Mix on Monday and expect to still use some on Friday, probably not a good plan.

Also be aware that Rodinal (clones) is a rather different developer character from D-76 (even diluted) -- there's very little sulfite in the working solution, and only a single developing agent instead of a superadditive pair, so you can expect to lose some speed compared to D-76 and see a significant increase in visibility of grain (though you're likely to also see an increase in perceived sharpness as a result of the grain increase).

 

[Kyle M.]

I have several bottles of Rodinal and I'm running out of Kodak D76 ( one pouch left ). I can mix the Kodak just fine with a gallon of water. But, my brain can't figure out how to mix Rodinal to make 1 gallon ( or so ) developer. I go through it pretty quickly, so I'd prefer to make a gallon batch. One shot is what I'm looking for at full strength.

Thanks again!

Are you planning to use that gallon all at once in one film developing session? Rodinal is not D76 you can't mix a gallon, develop some film, and then pour the Rodinal back into the gallon jug to develop with later. Vice versa you can't make up a gallon of Rodinal, develop some film using a small amount of that gallon diluted with water then dump it, and use the rest of the gallon down the road. The dilutions for Rodinal are 1:25, 1:50, and 1:100. I use 1:50 in my two reel (500ml) and three reel (1000ml) Paterson tanks. So in the 500ml tank that would be 10ml Rodinal and 490ml water, in the 1000ml tank it would be 20ml Rodinal and 980ml of water.

 

[wjlapier]

Bingo! The 2.5(6) ounces of concentrate per US gallon is the right ratio for 1:50 (or twice that for 1:25), but only mix what you'll use within the next few hours. Mix in the morning, and develop sixteen single rolls of 120, should be fine. Mix on Monday and expect to still use some on Friday, probably not a good plan.

Also be aware that Rodinal (clones) is a rather different developer character from D-76 (even diluted) -- there's very little sulfite in the working solution, and only a single developing agent instead of a superadditive pair, so you can expect to lose some speed compared to D-76 and see a significant increase in visibility of grain (though you're likely to also see an increase in perceived sharpness as a result of the grain increase).

I'll mix only what I need then. This is the original Rodinal I bought about 10 years go. I've used it recently at 1:50 ( 1+50? ) and it was fine.

 

[mrosenlof]

1:50 would normally be 1 unit of concentrate in 50 units of mixed solution. 1+50 is "typically" 1 unit concentrate + 50 of water. When you're at this sort of dillution it doesn't really matter. I'm pretty certain I don't measure my 500 or 490 ml of water that accurately.

 

[bripriuk]

Rodinal is one-time one-shot only, the diluted developer won't keep, Don't try a gallon at a time!

Brian P

 

[LouisGR]

It's not the question that's dumb, but the archaic measuring system. It's a nuisance in photography and also in cooking. I can't understand why the US doesn't use the metric system.

Louis G

 

[Horatio]

It's not the question that's dumb, but the archaic measuring system. It's a nuisance in photography and also in cooking. I can't understand why the US doesn't use the metric system.

Louis G

It's because we're special. Seriously though, no one wants the nightmare of changing the infrastructure. Although it could be a great way to resurrect the Works Progress Administration!

 

[titrisol]

I'll mix only what I need then. This is the original Rodinal I bought about 10 years go. I've used it recently at 1:50 ( 1+50? ) and it was fine.

1+49 or 1+50 makes little difference in dev.times. However, as long as you always do the same thing you'll get similar results.
I normally mix 7ml (measured with syringe sp +/- 0.2ml) diluted to 350ml total (measuring cylinder , +/- 5ml) for 35mm.

 

[Donald Qualls]

I can't understand why the US doesn't use the metric system.

Some parts of the US do use metric. My 1990 Aerostar had a mix of US and metric fasteners, I routinely use milliliters and grams in my darkroom -- but I reload in grains, because all the existing data is recorded that way. Heating and cooling equipment is sold in BTU rather than kilocalories or kilojoules, but we get our electricity in approximately metric-compatible units (watts are the same, seconds are the same, so a kilowatt-hour is 3600 kilojoules).

Legally, the US has been metric since the 1970s. The inch, pound, and other common "US Customary" measurements are legally defined in terms of meters, kilograms, etc.

 

[Wayne]

It's because we're special. Seriously though, no one wants the nightmare of changing the infrastructure. Although it could be a great way to resurrect the Works Progress Administration!

Right. We're bigger than they are so they can't make us no matter how much sense it makes. Scientists routinely use metric in the US, but science is a foreign language to many Americans.I've been using it long enough that I can do most common conversions in my head, or at least estimate them.

 

[Horatio]

Right. We're bigger than they are so they can't make us no matter how much sense it makes. Scientists routinely use metric in the US, but science is a foreign language to many Americans.I've been using it long enough that I can do most common conversions in my head, or at least estimate them.

To be fair, most commercial products that deal with volume and mass list metric and US standard values. Medicine switched to metric long ago, though OTC remedies still use teaspoon, etc.

So, are we still making a gallon of Rodinal?

 

[pentaxuser]

1+49 or 1+50 makes little difference in dev.times. However, as long as you always do the same thing you'll get similar results.
.

No, that's rubbish. I can instantly tell a 1+49 neg from a 1+50 neg processed at the same development time and that's even upwind at 1000 yards

pentaxuser

 

[Donald Qualls]

OTC remedies still use teaspoon, etc.

Some do. However, many have switched over (likely because there's so much variation in the spoons people use). Cough syrups now usually come with a dosing cup on top of each bottle; that cup is marked in 5, 10, or 20 ml amounts and the instructions give the dose in those units as well. Aspirin switched from grains (standard tablet was 21 grains) to milligrams (now 325 mg) decades ago -- I don't recall ever buying aspirin marked in grains, and that would go back to the 1980s.