greenest (least toxic, most eco friendly) developer?

Aside from Caffenol/vit c. solutions, which production developer would be the most eco-friendly? I'm thinking microdol x?

You may want to take a look here although I don't think they make a film developer:


http://www.digitaltruth.com/store/cart/Silvergrain-p-1-c-119.html

Regards,

Ash

All developers still have alkali, sulfite and have what is called a BOD and a COD which are respectively Biological Oxygen Demand and Chemical Oxygen Demand. These factors describe ecological impact in terms of Oxygen consumption and production of byproducts.

There are other chemicals present in developers which can present problems besides developing agents.

Another way to approach the problem is to use less concentrate per unit of working developer, so two developers that are similar will differ in bio-impact if one is diluted 1:9 and another 1:19 to make working solution. Another way to approach this is to have a developer that simply has higher capacity or tray/tank life. If you have a developer go bad every hour and have to toss it and mix fresh, this is worse than a similar developer that lasts a week.

These hypothetical examples should give you more to think about than a simple quick answer can give.

PE

Whatever developer you use will pale into insignificance on disposal compared to all the other household waste sent for treatment, unless of course you are a large processing lab.

Xtol's the best environmentally friendly film developer, but in all honesty after working in the field of recycling & waste disposal I was alays assured that developers posed no issues at treatment plants. The recycling company I used to work for were licensed to dispose many gallons per day and it was my job to liaise with the relevant authorities on behalf of other companies seeking licenses.

Ian

PE's reply is excellent. Forum discussions about the "green-ness" of developers usually deal only with the toxicity of developing agents, and completely neglect the oxygen-demand issue. I would also add that the manufacture of basic chemicals present in the developer has its own environmental impact -- some materials (e.g. ammonium salts) are very energy-intensive to produce.

Thanks Jordan. Your additions on energy consumption to make the basic chemicals was just what was needed.

PE

Photo Engineer said:

All developers still have alkali, sulfite and have what is called a BOD and a COD which are respectively Biological Oxygen Demand and Chemical Oxygen Demand. These factors describe ecological impact in terms of Oxygen consumption and production of byproducts.

Click to expand...

Just to nitpick, not all alkalis have a BOD or COD. Only ones with organic complents to them. So TEA has both BOD and COD, where as inroganics like carbonate, bicarbonate, boron-based like borax or Kodalk, or hydroxide, will have no BOD or COD.

Sulfite does have a BOD and COD, as does most stop baths - acetic and citric acid both do.

Phosphate promotes biological growth and can help give BOD but it has no COD.

Finally, BOD stands for Biochemical Oxygen Demand, as it is affected both things that chemically consume oxygen like sulfite and organics, as well as things that are nutrients to biological (i.e. bacterial) life, like phosphate or organic materials.

I can't pretend to keep up with the chem guys here, but I can make some suggestions for greener devs:
X-Tol, E-76 and Mytol use Vit. C and phenidone
HC-110, Ilfotec & Rodinal because you can use very little.
D-23, only two ingredients, metol and sulfite.
D-76H, the hydroquinone is removed.

Get a copy of Anchell's "Darkroom Cookbook". Some of these recipes are in the the book and they are easy to homebrew.

I think you misread that Kirk. Or I was unclear.

All developers have BOD and COD due to alkali, sulifite, TEA, PG, EG, HQ, Metol, Phenidone, Glycin, Amidol , Ascorbic Acid and whatever else they may contain depending on formula. So, since every developer contains one or more of the above, they have BOD and/or COD. So, a developer may contain Kodak with no BOD or COD, but then has HQ or Phenidone or AA or Sulfite and bingo, it does have BOD and/or COD depending on the formulation!

BOD (Biological Oxygen Demand) IIRC was the term we used back in the 60s and 70s, perhaps incorrectly but infrequently as BOD was much easier to say and spell. At that time, it was used a lot with Phosphates which promoted Biological growth, thereby Oxygen demand went up and so it promoted a high BOD.

I might mention that I was part of a team that developed a totally closed system that used disposable cubitainers to process film with no effluent. The wash water was reused and any water escaping the system was pure. The cubitainers were essentially bricks of pollutants. At one time, we considered using them for fuel. They were safe as long as the proper burning was observed.

PE

I like to think you were unclear ;^)

But perhaps I read it wrong. You're correct that all developers have both BOD and COD - but I was clarifying that not all developer components have both BOD and COD.

The oldest copy of Standard Methods I can find is 15th from 1980. They refer to BOD as "Biochemical" in that. Perhaps in years past, it was simply "Biological".

I hear a lot of people these days in environmental labs that ought to know better call it "biological".

Sodium ascorbate may be enough of an alkali to
activate phenidone. If so I doubt there exits any
other combination which would equal it in
eco-friendliness.

Over all the less chemistry needed per roll
of film or sheet of paper the more eco-friendly.

Another way to friendly is planning ahead.
Know ahead how much working strength will
be needed then prepare just that much chemistry.
A quality small capacity digital scale is a big help.
Throwing unused capacity down the drain is a most
eco-unfriendly act. Dan

It seems to me that Rodinal at 1:100 is pretty low on the scale of introducing more pollutants to nature.

If you were competing for least friendly, you'd have tough competition from most laundry detergents I think.