Fomado Exel problem.

[GeorgesGiralt]

Hello !
Two days ago I mixed one litre of Fomadon Exel ( said to be an Xtol like product ) using long boiled water and a very clean glass vessel.
After mixing as there was a very small remaining undissolved particles I filtered the solution and pour it into a clean brown glass bottle (I use only these for dev. solution, so the previous liquid will be, if any, a B&W dev.)
This morning I was planning to dev a couple of Tmax films. I was very surprised to found that the liquid is full of some sort of precipitate, half of it being in suspension, the other half has deposited at the bottom of the bottle. The precipitate is white, fluffy looking, and does not goes into solution if I shake the bottle.
Before I dump all this stuff to the sewer, do you have any idea of what went wrong ? and what should I do to prevent the problem in the future ?
Thanks for your answer !

 

[Tom Kershaw]

Georges,

I'm using a 5 litre batch of XTOL (mixed back in July) split into 2500ml containers, one for the working solution and the other for replenishment. The working solution contains a dark grey precipitate but was working fine the last time I used it. However, in the context of your 'Excel' developer it sound as though the dry compounds have been fully mixed into a solution. Kodak XTOL is very inexpensive. See: http://www.ag-photographic.co.uk/kodak-xtol-5l-363-p.asp

Tom

 

[Photo Engineer]

This may be happening, but is not supposed to happen.

Suspended material in any photographic solution is not good for the film. The particles can become trapped in the emulsion just like dust and dirt and appear as spots in the finished negative.

I cannot diagnose the problem, but I can say that this is not good.

PE

 

[GeorgesGiralt]

OK, gents.
I'll dump the stuff. The precipitate is covering quite all the liquid. So I wonder if I'll get it filtered I'll get enough to process one film !
As I've D76 and Xtol, I won't risk any film on this stuff.
Thanks

 

[:Francis:]

This may be happening, but is not supposed to happen.

Suspended material in any photographic solution is not good for the film. The particles can become trapped in the emulsion just like dust and dirt and appear as spots in the finished negative.

I cannot diagnose the problem, but I can say that this is not good.

PE

I have experienced this very problem with Fomadon Excel. When I've used up mine I don't think I'll be buying more of the stuff .

Francis I don't think.

Francis

 

[Alan Johnson]

See the MSDS:
www.freestylephoto.biz/pdf/msds/foma/Fomadon_Excel_W27_Film_Dev.pdf
Sodium pyrosulfite is sodium metabisufite which is acidic.My guess is that the other alkali not mentioned brings the pH to 8.2 and is reacting with residual calcium salts in the boiled water to form a precipitate.
This kind of thing happens all the time with developers having carbonate alkali,the precipitate is generally nearly colloidal and not a problem.But without seeing your precipitate it's just a guess.

 

[Photo Engineer]

Alan;

Colloidal solids in 35mm film can become trapped. I've said this over and over. If it becomes trapped, then it will be seen in enlargements as tiny white dots. So, beware and be forewarned.

PE

 

[GeorgesGiralt]

Well, Alan,
As I boil the water for a long time, I suspect that the calcium gets deposited on the kettle ! (And it is if I look at my kettle's bottom )
So there should be trace of calcium salt left on the water. (my municipal water is not so hard, anyway).
And I do not think a trace of calcium is able to convert ALL the product into precipitate as it is now.
But, I'm not a chemist...

 

[Anon Ymous]

Georges, boiling hard water can help and it will make calcium salts precipitate to some extent. Not all of it will get to the bottom though and you will need to filter that water to "purify" it.

 

[Alan Johnson]

I have 3x500ml bottles of Xtol left from a batch made up a couple of months ago using not boiled tap water and -aargh- on examination they have the fluffy suspension.I found that on shaking it goes away.This is the same as reported by Alessandro.
Fomadon Excel is apparently different in that the precipitate is reported not to dissappear on shaking and it may not be due to calcium carbonate.
I don't understand any of what is occurring,all that can be done is to make a note of it in case it is of later interest.