Developer stock solution, concentrating it?

[xwhatsit]

Hello,

Normally I use Ilford developers (mostly Microphen) by the 1 litre and use their re-use time-increase method. Haven't noticed any inconsistencies -- given that I use crappy old cameras, push film regularly, and guess the exposure (selenium meters aren't much good at night), there's a fair bit of noise clouding any re-use issues.

However I picked up four bags of 3.8 litre D76. Given the quantity of it, I thought I might go with the one-shot method with 1:1 and 1:3 dilutions.

The trouble is, 3.8 litres is quite a bit and might be difficult to store (what sort of bizarre quantity is 3.8 litres anyway? I thought it might be imperial measurements but that's only 0.8 of a gallon so that's not right). Rather than dividing the powder up, which is of course verboten and will earn you an ear-clip, can I instead dilute my to-make-3.8-litres powder into, say, 2 litres of water? Then of course when I prepare my working solution I dilute a little further (instead of 1:1, I go roughly 1:3 or thereabouts instead).

My naïve little mind sees no problem with this, apart from the mechanical act of dissolving that much powder in that little water.

Many thanks for any sneers or finger waggling you can supply.

 

[Steve Smith]

(what sort of bizarre quantity is 3.8 litres anyway? I thought it might be imperial measurements but that's only 0.8 of a gallon so that's not right).

3.785 litres is one US gallon. The US gallon is slightly smaller than the Imperial gallon.


Steve.

 

[xwhatsit]

3.785 litres is one US gallon. The US gallon is slightly smaller than the Imperial gallon.


Steve.

Whoo! Thanks for that. No wonder we standardised on the metric. Customary measures are mental.

 

[Steve Smith]

No wonder we standardised on the metric.

You speak for yourself - I'm still imperial!!


Steve.

 

[Gerald C Koch]

If you try to make up a 2X strength concentrate you will have problems with trying to get everything into solution. Even if you should be successful should the temperature in the darkroom drop you will get massive crystallization. For the amateur photographer such large sizes are really not a bargain when you consider storage life of the solution.

 

[Josh Harmon]

I usually buy the 1 gallon (3.78L) bags of D76. I then buy a 1 gallon bottle of distilled water and use the bottle that came in to store the developer. I have so far gotten about 14 rolls with about 20oz (600ml) left. I use it 1:1 or 1:3 exclusively. I also develop about 1 roll a week.

Josh

 

[michaelbsc]

... (what sort of bizarre quantity is 3.8 litres anyway? ... )

Why sir, that's how we keep the riff-raff out!!

 

[MattKing]

I use Kodak Polymax-T print developer. The smallest size it is sold in is 32 US ounces = 1 U.S. quart (.946 litre) of developer concentrate.

The label says 32 ounces, and that is how the contents measure out. If you look at the bottom of the bottle, however, it is embossed with - 1.0 litre!

I wish they just sold it by the litre.

In response to the OP, you will find it hard to dissolve the packages in 2 litres, but you may be able to dissolve them in something less than 3.8 litres. It may be worth your while experimenting - try 3.0 litres, for example.

Just remember, however, that you will need to vary the dilution of your stock to compensate for its "custom" nature (using 3.0 litres as an example, it would be 3.8/3.0 times as concentrated as the standard)

 

[pentaxuser]

Get two empty wine boxes( in the U.K. these come as 3 litre boxes so one isn't enough) make up the full 3.8L of stock solution and either part fill the two wine bags or completely fill one and use the 0.8L as quickly as possible. An empty PET bottle with a heavier than air gas such as Protectan should protect the 0.8L stock solution. Wine bags in boxes prevent air entering the stock solution as you decant it. You can expel the air in the bag by pressing it until the stock solution you have poured in reaches the neck of the bag then re-fit the dispensing tap.

I have done this with 1L of DDX and I am still using it a year later

pentaxuser

 

[xwhatsit]

Cool, thanks for the responses everybody.

I would've thought US gallons would be larger than gallon gallons, like their hamburgers.

How do they do stuff like LC29 and Rodinal then? Some sort of special absorbing chemical?

Don't think I could bring myself to drink 3 litres of cask wine for the sake of photography (Château L'Cardboard), but maybe I can scrounge up something big enough.

 

[MattKing]

These cube containers may be what you need:

http://www.porters.com/film-darkroom/film-darkroom-accessories/collapsible-chemtainer-gallon.html

No drinking necessary

 

[srs5694]

How do they do stuff like LC29 and Rodinal then? Some sort of special absorbing chemical?

You can dissolve different amounts of different chemicals in any given solvent (such as water). Likewise, you can dissolve different amounts of a given chemical (such as metol) in different solvents. Thus, you can change the concentrations of stock solutions by altering what chemicals they contain, either as active ingredients (metol, hydroquinone, sodium sulfite, etc.) or by changing the solvents used (water, TEA, etc.). Of course, if you make such a change, it's not the same developer any more, although in some cases it may act very much like the original -- or it might not.

You can find formulas for some common developers, such as D-76 and Rodinal, online or in books. (These formulas may not describe the actual commercial products, which may contain proprietary and trade-secret changes; but they'll be close.) The right chemistry texts will tell you how much of specific chemicals you can dissolve in particular solvents. I don't happen to know what these references are, but I'm sure some here (such as PE) do.

I don't know much about LC29, but Rodinal is very different from D-76 on a chemical basis -- it uses a different developing agent (p-aminophenol in Rodinal, vs. metol and hydroquinone in D-76), a different activator (sodium or potassium hydroxide in Rodinal, vs. borax in D-76), and so on. Both use water as a solvent. I don't know offhand what ingredient is most limiting to how concentrated you can make D-76.

 

[2F/2F]

If you try to make up a 2X strength concentrate you will have problems with trying to get everything into solution. Even if you should be successful should the temperature in the darkroom drop you will get massive crystallization. For the amateur photographer such large sizes are really not a bargain when you consider storage life of the solution.

Perhaps it depends on the water used or something else, because I always used to make up my D-76 or ID-11 stock at double strength, and I never had any of these issues. It went right into solution and stayed there. I would let it sit for at least a day or two before using it, as Kodak recommend. I found two quarts to be easier to store and keep air free than four quarts.

 

[Bill Burk]

I mixed a gallon of developer and poured into four brown plastic quart bottles yesterday. Three of the foil-cardboard seals on my old bottles were still good but one rotted out so I replaced it. Usually I replace all the seals - I can cut four seals out of the big seal that comes with a jar of peanut butter. I squeezed air out, cinched down the lids and marked the mix date on the labels.

I'll use it 1+1 - a pint of stock solution to a pint of water - either developing 2 rolls 120, 4 rolls 35mm in steel tanks or 7-14 sheets of 4x5 in open trays.

If I had a Paterson tank or if I use the Nikor 4x5 tank I would still mix a pint of stock solution but I would dilute it more as needed to make sufficient volume to cover the film.

If I leave a half-bottle for a week, I'll just finish it off the next time. If I can't remember when I opened a bottle, I'll just open another one if I'm doing critical shots.

My point is - quart bottles are a convenient way to keep and use a gallon of chemistry.

 

[fotch]

I mix up D76 stock and store in 16 amber glass 250ml bottles with no air. Same with Xtol except 20 bottles.
Last a long time. Use one shot or 1:1. If using larger tank, just use several bottles. Always fresh.

 

[xwhatsit]

OK -- so maybe I can get away with it. Given that I have four bags of the stuff I got for next to nothing and it's nearing expiration date (although sealed bags of powder should last for quite a while past expiration, no?) I may just experiment.

Cheers!

What do you people do who mix up large quantities and decant into smaller bottles do? Mix it in a bucket (having marked where 3.8L is on the side so you know how much to top the water up) or something?

 

[2F/2F]

OK -- so maybe I can get away with it. Given that I have four bags of the stuff I got for next to nothing and it's nearing expiration date (although sealed bags of powder should last for quite a while past expiration, no?) I may just experiment.

Cheers

What do you people do who mix up large quantities and decant into smaller bottles do? Mix it in a bucket (having marked where 3.8L is on the side so you know how much to top the water up) or something?

First, follow the directions, except for the last step. Mix the powder into 3 quarts (liters will do). You then have to add water until the proper total volume is reached. I don't have a big graduate with a one gallon mark. I did this by filling up 3/4 of a quart at a time (you can use 750 ml), and then up to the quart line with water and mixing. Then I poured it into a gallon jug temporarily. I did the same with following quarts (Four quarts make a gallon.). On the fourth quart, you will start out with a little more than 3/4 of a quart, due to the volume added by the powders. Just fill with a little less water to the quart ling. Then I rotated and inverted the bottle gently, and decanted the fresh solution into 8 oz. (250 mL) glass bottles.

You can do something similar using liters if you have a five liter container (as opposed to the one gallon one I used). Just fill a one liter graduate 3.8 times, pouring the solution into the five liter container after you mix each liter. Use 3/4 stock and the rest water for each liter you dump into the big jug. On the last 800 mL, pour in the remaining solution, and add water up to the 800 mL line, mix, and then dump into the big jug. Mix it all together by gently rocking and rotating (not shaking) the big jug, and decant.

Of course, a 5 L graduate would be ideal, but do you have one lying around?

 

[cmacd123]

I have a big jug from the Auto Parts store. I suspect it was intended for mixing Glycol. It is marked in both liters and US measure. (the US gallon is based on the Imperial WINE Gallon)

 

[Steve Smith]

Could it be made up to the full 3.8 litres then boiled to distil off the excess water?

Not very practical I know, just a curiosity question.



Steve.

 

[Ian Grant]

Reverse Osmosis, that's what it was originally designed for, concentrating fresh Orange juice, would work for developers etc but not be practical. Boiling would be detrimental to the developing agents, sulphite etc.

Ian

 

[JDP]

I sometimes use these 3.8 litre packs of D76. I weigh it and divide by 3.8 (allowing a little for the weight of the packet). Then I know how much to weigh out for a given volume of stock. Seal the pack up again with electrical tape. Seems to work for me, though I guess it could be a problem if the pack was re-opened too many times.

Of course, I clip myself around the ear each time I do this....

 

[Mike Wilde]

The big killer in concentrating film developer is the amount of sodium sulfite they contain. Some approach 100g per litre of stock solution. I have worked (actually madly experimented) on concentrating Microdol X, which is a sod sulfite rich developer. I mixed the normally makes 3.8L packet of developer into about 1L of heated to 40C propelyne (sp?) glycol. All ingredients except for the sulfite would dissolve. I would filter the mix though a coffee filter to take off the sulfite that would not dissolve, and then proceed to mix the undissolved sod sulfite in progressively larger volumes of hot water until it would all dissolve.

It turned out that approximately 2L of water plus 1L of glycol was needed to make up the 3.8L of stock solution. Volume wise this is not much of a savings, but for longevity it sort of turns microdol x into something like HC-110; i.e. the developing agents are dissolved in a medium that contains no oxygen able to be scavenged by the developing agents in the solution.

The out of date stock solution and initail mixing and filtration effort causes some loss of developer activity, so a new developig time was needed to be determined by experimentation. Once this time was established, however, it has remained constant since I did the original mix up. I mixed up a litre of working solution two weeks ago, using 18 month old concentrated stock, and the developer is still working fine.

This approach was inspired by Pat Gainer's PC-TEA experimentation.

 

[srs5694]

Given that I have four bags of the stuff I got for next to nothing and it's nearing expiration date (although sealed bags of powder should last for quite a while past expiration, no?) I may just experiment.

Most manufacturers are pretty conservative about expiration dates on photochemicals. That said, it can go bad, even in powdered form, particularly if the bag is punctured or defective. (Internet "wisdom" is that packaging problems were to blame for many of the early XTOL "sudden death" problems.)

Certainly you're better off keeping an unopened bag in powdered form for as long as possible, rather than mixing it up now and storing it as a liquid.

What do you people do who mix up large quantities and decant into smaller bottles do? Mix it in a bucket (having marked where 3.8L is on the side so you know how much to top the water up) or something?

I've used both small plastic garbage pails and buckets for this purpose. I once bought a translucent paint-mixing bucket with quantities marked, but the quantity lines were so imprecisely drawn that they were useless.

 

[fotch]

............What do you people do who mix up large quantities and decant into smaller bottles do? Mix it in a bucket (having marked where 3.8L is on the side so you know how much to top the water up) or something?

Exactly. I use a large bucket, I thinks its 2 gallon in size, that has a pouring lip on it, and I made my own markings for the quanities, much like a large measuring cup, and only use it for mixing chemicals.

 

[MattKing]

A well rinsed 1 US gallon (3.8 litre) plastic milk bottle would work fine for initial mixing - just be sure to decant into smaller, more appropriate bottles for subsequent storage.