Help diagnose my precipitant

[Rich Ullsmith]

Here's the process. Fiber paper in dektol, 30-45s water stop/wash, then two bath fix with TF-4. Then a 10-15m sodium sulfite bath with intermittent agitation, then final wash (in this case, maybe 20-30m).

At the end of the wash, the bottom of the tray has a healthy amount of dark gray sandy precipitant. It's not dirt or sand . . .not possible. (Plus it doesn't "feel" like dirt or sand.) We have well water, but it's heavily filtered prior to entering the storage tanks in the house, which I inspected inside and they are clean. The house is new construction, so no corroded pipes.

The precipitant does not go into solution either with sodium sulfite or fixer.

This is not the first time this has happened.

I can only recall this happening with fiber paper processing . . .meaning only when I use a sodium sulfite bath prior to final wash.

Once per month, I drop two chlorine tabs in the water tanks to inhibit any growth . . .the tanks are 250 gallons and H2O is cycling through daily, so 2 little chlorine tabs should not make a difference . . .?

Any differential opinions on what the source of this is, I'm all ears.

 

[frank]

You may have discovered another way of synthesizing crystal meth. :w00t:

 

[gzinsel]

could you take a picture ? at the immediate moment, I am not sure why/how you wash your prints? I mean, . . . I guess this is not a vertical wash container? correct? well my two cents would be that in a good wash system, the heavy salts, float/sink to the bottom, and additional water over flows the top, meaning if you do not have a "drain" of some sort at the bottom of the tray, "the heavies" just sit there, they do not leave! if enough heavy salts sit there long enough and mix with compounds in the water, you would get a "concentration" of mixed salts at the bottom of your tray, that can not leave because there is no drain area, and too heavy to go over board!!! thats the best I can come up with now, I hope that helps.

 

[Gerald C Koch]

What is the purpose of the 10 to 15 min sodium sulfite bath. If it is used as a wash aid then the time in the bath is far too long. In addition if this bath is not acidified then there is a chance of calcium sulfite precipitating from hard water. Adding a calcium chelating agent would also help.

Here is a formula for a HCA very similar to the Kodak product.

Sodium sulfite, anhy 100 g
Sodium bisulfite 25 g
EDTA tetrasodium salt 2 g
Sodium citrate 5 g
Water to make 1 l

 

[Sirius Glass]

You may have discovered another way of synthesizing crystal meth. :w00t:

I heard that the allergy season is so bad that the meth labs are converting meth back into Sudafed! :w00t: :w00t:

 

[Rudeofus]

Since TF-4 is plenty alkaline and normally mixed with tap water, we should assume that TF-4 contains a powerful Calcium sequestering agent. Could you check whether TF-4 would not even dissolve small amounts of this precipitate? Test like this:

• Take a beaker with 250ml of TF-4
• Put a few small grains of this mysterious precipitate into the beaker
• Let sit somewhere for a day
• Check whether grains still sit on the bottom of beaker

If TF-4 indeed dissolves the grains, as Gerald and I would suspect, you can either use Gerald's recipe, or if you want to do it on the cheap, just add equal amounts (somewhere between 1 and 10 g/l) of Sodium Carbonate and Citric Acid to your Sulfite bath until it turns clear. Be careful with the Citric Acid, or your Sulfite bath will smell awfully like rotten eggs. That smell would come from Sulfur Dioxide, which is quite toxic BTW. If you notice the smell, add Sodium Carbonate until it goes away!

One more thing: Gerald's recipe looks very concentrated to me, I think you need to dilute it at least 1+4 to make working solution from it.

 

[Xmas]

What is the purpose of the 10 to 15 min sodium sulfite bath. If it is used as a wash aid then the time in the bath is far too long. In addition if this bath is not acidified then there is a chance of calcium sulfite precipitating from hard water. Adding a calcium chelating agent would also help.

Here is a formula for a HCA very similar to the Kodak product.

Sodium sulfite, anhy 100 g
Sodium bisulfite 25 g
EDTA tetrasodium salt 2 g
Sodium citrate 5 g
Water to make 1 l

I get even the Kodak HCA to precipitate after some use the Kodak power is cheap so I discard earlier now.
Gerald's formula may be better.

My faucet water has solids come out on turbulence so is very hard.

I think as mentioned the formula is stock with different dilutions for paper or film.

 

[Xmas]

The formula Gerald posted would typically be diluted 1+4 or 1+5 for use.

While plain alkaline sodium sulfite solutions can precipitate calcium sulfite from hard water, if that's what's happening wouldn't Rich have observed it directly when he mixed the sodium sulfite bath (ie cloudy solution)? And can calcium sulfite be dark grey?

Kodak do provide life time eg for volume usage and time in 1:4 dilution in stock bottle.
Not tried sodium sulphite by itself.

 

[Gerald C Koch]

Typically when a certain compound precipitates from solution it can bring down other compounds as well These can change the color of the precipitate. For example when you boil water to remove the temporary harness not only does calcium carbonate come out of solution but also any iron compounds. These tint the precipitate tan rather than the expected white. So it is plausible for the OP to see a gray precipitate.

The formula that I posted should be used just like Kodak HCA. This applies to dilution and times.

 

[Rich Ullsmith]

I am thinking along Michaels line: I don't get any precipitant when initially mixing NaSO3 with my house water.

Next occurence, yes I will retest to see if TF-4 will put it into back into solution. My own test was with working TF-4, and I only gave it a couple minutes.

Again, I am convinced this is a chem problem and not a debris problem in the plumbing. This would have shown up in the wife's bath long ago.

I have everything in Gerald's recipe on hand, minus the EDTA, so I will give that a blow. Thanks everybody.

 

[Rich Ullsmith]

Also, the 10-15m clearing bath is arbitrary, I go on to do other things and agitate every once in a while. I seem to recall the guidline of 5m with constant agitation or 15m without. Anyways, I have never experienced clearing problems with this method.

 

[Photo Engineer]

TF-4 is very highly buffered. You see this in the white precipitate that covers the bottom of a bottle of concentrate. TF-4 cannot be mixed in small parts. The entire bottle must be mixed at one time for later use. This problem was fixed in TF-5.

In any event, improper use of TF-4 could lead to reprecipitation of part of the buffer. IDK.

Just a guess.

I agree with Jerry though. That Sulfite treatment is too agressive.

PE

 

[Rich Ullsmith]

Couple of questions here then, sort of off topic but I am interested. "Can't mix TF-4 in small amounts." Is this to say, I cannot take a gallon of stock TF-4 and pour off a quart to make a working solution? I must dilute the entire gallon, and have 4 gallons of stock on hand?

And concerning the "aggressiveness" of the sulfite treatment. What would the symptoms of that be? I know what the symptoms of lack of clearing looks like in toning and bleaching.

What would "improper use of TF-4" look like? I follow the Toning Book procedure for 2-bath, never with a problem. Don't mean to be a wise guy, but could you give me an example of improper use? Perhaps there is something here I am not thinking of.

 

[Photo Engineer]

Look at a bottle of TF-4 concentrate. It is in 2 layers. You cannot evenly get a part of those 2 layers, so yes, as said many times before, you must use all of the TF-4 at one time. That is, unless you have an excellent mixer, or unless you heat the concentrate until it becomes clear. It is mixed hot at the plant and is clear. Once it cools, it separates into 2 (unequal) parts. You must warm it or shake (stir, mix, or whatever) until the mixture is uniform.

Aggressiveness means too much hypo is removed and too much sulfite is put in. Read the article by Ctein on this. Over treatment such as this or even washing can create problems.

Improper use would be to pour off the clear upper layer of TF-4 and dilute it and use it for the first fixer and use the bottom cloudy stuff as the second fixer. BaaaaaaD! Improper use of anything is too long or too much. You can overwash and have the emulsion lift off the support for one example.

PE

 

[Rich Ullsmith]

All news to me. Obviously, shake the fixer before diluting. And again, not to be a smart alec but nothing you have outlined above is consistent with my experience. Thanks for the details, guess I need to read up on it.

 

[Doremus Scudder]

...
Aggressiveness means too much hypo is removed and too much sulfite is put in. Read the article by Ctein on this. Over treatment such as this or even washing can create problems.

PE

Ron,

Just a question about wash-aid times: Ilford's WashAid seems very similar to Kokak's HCA. They recommend a 10-minute treatment with agitation. Is there a bigger difference between the two products than I am aware of?

TIA (and sorry to the OP for the off-topic question).

Doremus

 

[Photo Engineer]

Doremus, Rich, both Kodak and Ilford have done research on their products and determined what they believe to be the optimum times for treatment using their HCA, but basically they are both Sodium Sulfite solutions. This is based, in part, on extensive image stability tests at Kodak. They look at fade, yellowing and bronzing among other things and include light, heat and humidity. Lately they have added atmospheric pollutants as well, to the mix.

Now, to be honest, aggressive treatment is possible, and this means removal of too much hypo. This problem does not show up for several years though in the worst cases, and does not show up at all if the print is properly toned. That is why I don't use HCA as it is just another chemical to store and to get rid of and there is also the worry that the Sulfite goes bad and forms the Sulfate, thus losing any benefit. Read the Ctein article for a good insight to this problem. He thought he was doing good by removing virtually all hypo, but had problems down the line.

As for my prints, I have untoned, un-HCA treated prints from the '50s that look just fine today, and having worked in a photofinishing lab for years, I know that none of his prints or films were treated. They were just washed and dried (film got the Photo Flo treatment).

Being a chemist though, I know it is bad to use a solution that has separated unless I take some action to remedy the situation. Maybe this should be more of a known issue, but I have never heard of problems with TF-4.

PE