Ilford DDX Developer Question

Nick Ventura ,

So I am looking into getting a new developer (previously used d76) and I was thinking about getting Ilford DDX as I will be mostly shooting ilford hp5 and delta plus the occasional trix and tmax but I have a few questions. I was reading and it says its better to use "one shot" but are you able to pour it down the drain after using in the US? Also how much would i mix up each time if I develop 1 or 2 rolls in a paterson super system 4 tank and dilute it 4 parts water to 1 part dev? Thanks all and if anyone could recommend to me a good fixer to go along with this it would be much appreciated.

Responses

Alan Marcus , Apr 20, 2014; 05:51 p.m.

Yes it will be OK to pour all you photo effluents down the drain.
First, it is likely not possible for a darkroom hobbies to harm a municipality sewer treatment system. That being said, there are lots of myths and few truths about photo effluents and their toxicity. Municipalities set limits for silver. Some silver compounds are toxic thus municipalities with a desire to protect the environment set limits on the silver content that can be discharged into a sewer system. Generally this limit is 5 parts per million however some set the limit at ½ part per million. You will need to check with our local sewer system to find out their limits. The good news is, the silver is not in the developer, it is in the fixer.
Before going further, a commercial photo lab needs to be informed and in compliance. A home hobbyist likely can’t impute anything that will do harm. As I said the biggest no-no is silver. In actuality a photo lab does output toxic silver however the half-life is likely only 15 minutes. The silver we output quickly complexes with the sulfur of the fix bath. The silver effluent reverts to silver sulfide which is inert. This is satisfying for us but municipalities use tests that show silver and they are not impressed by the fact that silver sulfide in inert.
Actually have more to fear from two other items, one is oxygen demand that they might know about and the other is chlorine demand that they probably don’t know about. Our photo effluents like human waste begin to take on oxygen as soon as they enter the sewer system. At the treatment plant they pump and aerate to get oxygen into solution. This oxidation process renders human waste and most photo waste inert. If they fall to satisfy the plants effluent as to oxygen demand, the plant effluent will compete with aquatic life for oxygen and a fish kill or algae bloom could occur. Big photo labs add a burden to the municipal treatment plant.
Chlorine demand is another issue. Our fixer is the same stuff used by tropical fish hobbyist to rid tap water of its toxic to fish chlorine. The stuff in the fixer causes chorine dissolved in water to effervesce out of solution. At the treatment plant the last step is to add chorine to kill harmful germs and virus. A big photo processing plant will force the treatment plant to double or triple the amount of chlorine they must add. This is costly, especially if they fail to get the chlorine up to specification as the Federal Government will fine them big time on a daily basis.

Now that you know all this, don’t worry, your home photo lab can’t do the municipal treatment plant any harm. Photo chemical makers advise against discharging to a septic tank. Some fear that the chemical will interrupt the natural action. Test after test have proven that home septic tanks thrive on photo effluent. The problem with all of this is – municipalities are frightened and rule against most any chemical influx. This is a key point for the digital darkroom.

John Shriver , Apr 20, 2014; 07:25 p.m.

B&W developers aren't an issue for municipal sewerage. Spent fixer is, and it's trivial to address it. Pour your spent fixer into a bottle with a ball of steel wool. Let it spend a month there, and the silver (which is the hazard) will have plated onto the steel wool.
Or, any decent photo lab should open your spent fixer with open arms, run it through their silver recovery system, and they will get a credit for the silver that they recover.

Nick Ventura , Apr 20, 2014; 08:57 p.m.

Thanks guys for the responses!
Also how much would i mix up each time if I develop 1 or 2 rolls in a paterson super system 4 tank and dilute it 4 parts water to 1 part dev? And can anyone recommend me a good fixer for those films? Thanks!

Alan Marcus , Apr 20, 2014; 09:56 p.m.

To determine volume needed, do a trial run filling the tank with water. Add sufficient water to cover the reel plus 10% for good measure. Now pour off the water into a measuring vessel. Your goal is 4 parts water to 1 part developer. Let’s say your test revealed that you needed 300ml for one reel and 630ml for two reels.
First we find the total number of parts. This will be 4 water 1 developer = 5 parts total.
For the one reel 300ml ÷ 5 = 60ml – one part = 60ml – this will be the volume of developer. Water volume will be will be 300 – 60 = 240ml water.
For two reels 630 ÷ 5 = 126ml per part thus developer volume is 126ml. Water volume is 630 – 126 = 504ml.

As to the fixer:
Modern film all fixes using any Rapid Fix formula. This will be easy to buy. Dilute the concentrate to make a working strength solution. Likely three parts water one part fix concentrate.

Test the working strength fixer – in the light swish a cut-off portion of the tongue in the fix. Observe and time this action. The film goes into the solution opaque and soon turns transparent. That will be the clear time. Double the clear time will be the correct fix time.
If you worry about the silver in fix, take it to a local photo processor for disposal. The addition of steel wool to the spent fixer is an ion exchange reaction. The silver trades places with the iron. The spent fixer now contains iron, the silver falls to the bottom of the vessel as sludge. The reaction is fast, likely complete in one or two hours. The silver you collect from a dozen rolls of film will be far less than a gram (the weight of a raisin).

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