Particulate in freshly-mixed DIY ECN-2 Developer

[originalwinslow]

I have recently started mixing my own ECN-2 developer using the published EK recipe. I have noticed that a particulate of some sort begins to form shortly after the developer sits in stasis for a few minutes in the storage bottle. It almost looks like fluffy snowflakes. I have not seen this type of coagulation in other developers, ECN-2 or otherwise, and would prefer have clear chems. I have used the developer with good results.

Anybody know what may be causing this? I use distilled water and mix thoroughly for 10 minutes before storing.

 

[Rudeofus]

Just a few quick questions:

1. Did you use DI water or tap water?
2. Did you add the recommended sequestering agent?
3. What did you use as "Kodak AF-2000" ?

 

[originalwinslow]

Just a few quick questions:

1. Did you use DI water or tap water?
2. Did you add the recommended sequestering agent?
3. What did you use as "Kodak AF-2000" ?

Distilled water. I did not include either the Anti Calcium or AF-2000. It was my understanding that at least the anti-calcium is unnecessary when using distilled water.

 

[Rudeofus]

Distilled water. I did not include either the Anti Calcium or AF-2000. It was my understanding that at least the anti-calcium is unnecessary when using distilled water.

Yes, that's the assumption, but it may also depend on the quality of your raw ingredients. If you are curious: you can try mix just the "cheap bulk ingredients", sulfite, carbonate and bicarbonate in the recommended amounts and see, whether you get these flakes.

 

[originalwinslow]

I will try that and see. Everything besides the bicarbonate is from the trusted US chemical supplier Artcraft.

 

[koraks]

What is the order in which you mixed the ingredients? When you added the CD3 developing agent, can you describe how it looked as it dissolved?

 

[lamerko]

I've never seen anything like this with ECN-2 chemistry. But I've seen it with an old Agfa process with CD-1. Maybe because of the age of the chemical, I don't know...
By the way, if you add CD-3 last (after the solution is already highly alkaline), there's a good chance that the neutralization of the developing agent will go the other way...

 

[koraks]

if you add CD-3 last (after the solution is already highly alkaline), there's a good chance that the neutralization of the developing agent will go the other way...

Not sure what you mean by 'neutralization of the development agent will go the other way'; can you elaborate?

What I do notice, and am alluding to in my earlier post, is that if you add powdered CD3 to an otherwise finished developer formula, the CD3 tends to form little magenta-colored hydrophobic/oily pellets that are very difficult to dissolve. This does not happen if you dissolve the CD3 in (tap) water and then add that solution to the mixed developer.

 

[lamerko]

Not sure what you mean by 'neutralization of the development agent will go the other way'; can you elaborate?

Well, CD-3 is strongly acidic - pH around 1. At the same time, the working solution will have a pH above 10, maybe around 11. Adding CD-3 (as a powder) at this stage leads to "bubbling" and the corresponding neutralization to some salt, I'm not sure what hydrolysis occurs. But... visually it looks like unpleasant greasy rags - I've thrown away chemistry because of this...

 

[koraks]

But... visually it looks like unpleasant greasy rags

Yeah, I think we're talking about the same thing, although I've always seen it in the form of globules. I suspect something similar is happening in OP's case. Btw, in cases like these, it can help to add a little ethanol to the developer to get the CD3 to redissolve.

 

[originalwinslow]

What is the order in which you mixed the ingredients? When you added the CD3 developing agent, can you describe how it looked as it dissolved?

Order of mixture was : distilled water @ 105F - sodium sulfite - sodium bromide - CD-3 - sodium carbonate - sodium bicarbonate - water to a liter. I got a pH reading of 10.2. When I added in the CD-3 I did see some bubbling but it quickly dissipated and the solution mixed clear. No pink greasy pellets.

My solution was totally clear while mixing, particulate begins to form when agitation stops.

One recipe mentioned that after adding CD-3 you should thoroughly mix for 10 minutes before adding the carbonate and bicarbonate. I tried this on my second batch, but noticed that the CD-3 in the solution began to oxidize pink after about 5 minutes. I scrapped the extra mix time and quickly added the final two ingredients. This apparently halted the oxidization. I can try mixing in the CD-3 for the full 10?

Regardless, the developer is giving me good results.

Well, CD-3 is strongly acidic - pH around 1. At the same time, the working solution will have a pH above 10, maybe around 11. Adding CD-3 (as a powder) at this stage leads to "bubbling" and the corresponding neutralization to some salt, I'm not sure what hydrolysis occurs. But... visually it looks like unpleasant greasy rags - I've thrown away chemistry because of this...

I have seen thin gray "greasy rag" particulate that forms on the interior surface of the storage bottle for D-76 developer. I ignore it...

 

[koraks]

OK, thanks for the details. I'd propose you do the following:
* Adhere to the same mixing order you've been doing for now, up to the point where you would normally add the CD3.
* Dissolve the CD3 in e.g. 50ml of water (quantity isn't critical; it's quite easily soluble). There will be some minor discoloration, but not much. It doesn't hurt.
* As soon as the CD3 is dissolved in the water, add this solution to the otherwise finished developer. Mix briefly to homogenize.

This is the approach that works well for me; no floaters etc. I do get a milky/misty solution because I use tap water and no chelating agent. If you use demineralized water, the solution should stay clear.

 

[originalwinslow]

OK, thanks for the details. I'd propose you do the following:
* Adhere to the same mixing order you've been doing for now, up to the point where you would normally add the CD3.
* Dissolve the CD3 in e.g. 50ml of water (quantity isn't critical; it's quite easily soluble). There will be some minor discoloration, but not much. It doesn't hurt.
* As soon as the CD3 is dissolved in the water, add this solution to the otherwise finished developer. Mix briefly to homogenize.

This is the approach that works well for me; no floaters etc. I do get a milky/misty solution because I use tap water and no chelating agent. If you use demineralized water, the solution should stay clear.

Thanks, just one question: Same mixing order until the CD-3, then you say add the CD-3 to the otherwise finished developer...so add the dissolved CD-3 last? Or add before the carbonate and bicarbonate as previous?

 

[koraks]

so add the dissolved CD-3 last?

That's what I do. You could also do it the other way around; I don't expect it to make any difference really.

 

[originalwinslow]

Makes sense why it was mentioned that the 10 min mix should specifically occur after adding CD-3.

The pink hue made me think there might be an unacceptable level of oxidization occurring so I added the other ingredients before 10 minutes.

I will try pre-dissolving and report back.

 

[koraks]

A little pink discoloration is not necessarily worrisome, although I don't really encounter it in the workflow I described. When you add the CD3 to a small volume of water, it's so concentrated that it basically doesn't want to oxidize within the short period of time before it goes into the main mix. At that point, there's the small amount of sulfite to protect it. When I mix this developer, it ends up virtually colorless.

 

[lamerko]

To make my job easier, I already make two concentrates. The first one is with sulfite and bromide, the second one is with carbonate and bicarbonate.
According to Kodak's instructions, the order of CD-3 falls right between the two, which is very convenient. And yes, there are instructions to mix for 10 minutes. This has always been strange to me, because CD-3 dissolves very quickly for me. But when I think about it - it is apparently to prevent a reaction to a highly alkaline environment...
Do not put the carbonate in PET bottles - they will decompose
So whenever I prepare a working solution, I dilute A, pour in the required amount of CD-3 powder - it dissolves completely very quickly, add water and add concentrate B. In this way, CD-3 has never bubbled, decomposed into rags or given any indication of oxidation (color change). However, once I forgot to put CD-3 after the first concentrate and put it in at the end - I threw it all away.

 

[originalwinslow]

To make my job easier, I already make two concentrates. The first one is with sulfite and bromide, the second one is with carbonate and bicarbonate.
According to Kodak's instructions, the order of CD-3 falls right between the two, which is very convenient. And yes, there are instructions to mix for 10 minutes. This has always been strange to me, because CD-3 dissolves very quickly for me. But when I think about it - it is apparently to prevent a reaction to a highly alkaline environment...
Do not put the carbonate in PET bottles - they will decompose
So whenever I prepare a working solution, I dilute A, pour in the required amount of CD-3 powder - it dissolves completely very quickly, add water and add concentrate B. In this way, CD-3 has never bubbled, decomposed into rags or given any indication of oxidation (color change). However, once I forgot to put CD-3 after the first concentrate and put it in at the end - I threw it all away.

This method seems efficient for simplifying the mixing process, but chemically how does it differ from adding everything one by one? The bromide/sulfite solution would be the same, so why does the CD-3 not bubble when introduced in the manner you describe? Just curious.

Also, I store all my chemicals in PET bottles...perhaps this is poor practice but giving a quick squeeze is far more convenient than topping up glass bottles with marbles or adding inert gas.

 

[lamerko]

When the pH rises above 11, PET bottles start to break down and all the chemistry leaks out. The carbonate concentrate is enough to destroy a PET bottle, but the ECN-2 stock solution has a lower pH, which these bottles can withstand.

Whether I will proceed like this with concentrates for convenience or direct dilution - I don't think it matters. Maybe the only difference is that I mix the chemistry at lower temperatures - usually at room temperature, up to 20C-30C degrees. I use a magnetic stirrer, which does everything for me
The other thing that comes to mind is that the pH of the sulfite can vary. For example, mine may have a lower pH, and yours - a higher one. I don't know...

 

[koraks]

why does the CD-3 not bubble when introduced in the manner you describe

The CD3 is added to a mixture of bromide & sulfite, which isn't alkaline enough to make the CD3 fizz as it hits the water.

 

[originalwinslow]

When the pH rises above 11, PET bottles start to break down and all the chemistry leaks out. The carbonate concentrate is enough to destroy a PET bottle, but the ECN-2 stock solution has a lower pH, which these bottles can withstand.

Whether I will proceed like this with concentrates for convenience or direct dilution - I don't think it matters. Maybe the only difference is that I mix the chemistry at lower temperatures - usually at room temperature, up to 20C-30C degrees. I use a magnetic stirrer, which does everything for me
The other thing that comes to mind is that the pH of the sulfite can vary. For example, mine may have a lower pH, and yours - a higher one. I don't know...

Good to know! What is your procedure for mixing the concentrates and diluting? E.G. Xml of solution 1 (containing Xmg of bromide and Xmg of sulfite) contains enough to mix X liters of working solution etc. I assume these concentrates are inert enough to be stored almost indefinitely. Also, why mix at a lower temperature? Does that affect solubility?

The CD3 is added to a mixture of bromide & sulfite, which isn't alkaline enough to make the CD3 fizz as it hits the water.

I was wondering how this procedure would differ from adding the ingredients one by one in terms of alkalinity of the solution that the CD3 is introduced to.

 

[originalwinslow]

Back with an update:

Pre-dissolving the CD-3 in 50ml distilled water had no effect on the formation of particulate in the solution. I believe the particulate is calcium, perhaps dried residue from the beaker that I did not rinse with distilled water prior to mixing. I have yet to try mixing with COMPLETELY clean materials, but regardless it has become clear that keeping tap water (and subsequently calcium) out of the developer will essentially be impossible.

If it indeed is calcium I suppose I will have to accept that particulate will form if I don't add the anti-calcium ingredient.

I wonder if this particulate affects the degradation or efficacy of the developer. Does anyone have information on what the effects of calcium particulate in developer are?

 

[koraks]

Calcium precipitates resulting in cloudiness is indeed common, but unrelated to the CD3 as such. If you mix the developer including the carbonate, but without CD3 and you don't get a precipitate, the precipitate is not calcium.

I wonder if this particulate affects the degradation or efficacy of the developer.

If it's calcium, then no. It's harmless.

 

[lamerko]

Calcium carbonate is extremely poorly soluble in water, but sometimes there are waters that are rich in calcium bicarbonate, which is obtained by interaction with carbon dioxide. Accordingly, when heated above 80 degrees Celsius, practically all dissolved calcium under any salts will precipitate. As a bonus - dissolved oxygen, which is in very large quantities in tap water, will also be drawn out. This is good, because the formula of ECN-2 developer does not contain a preservative, except for the minimum amount of sulfite.
Just boil your water, making sure not to stir it much while it cools.