Tetenal Gold Toner has orange precipitate - exhausted?

[simgrant]

Hi All,

I purchased 1L of Tetenal Gold Toner about a year ago and have used it on many prints (maybe 50+) which is lucky as it is damn expensive. I had not noticed in this time any degradation in performance over except maybe that warmtone papers did not give such a pronounced blue as they did when the solution was new. I haven't used the solution for a few months as other things in life have taken priority. I recently used it again to alter the colour of a sulphide toned print (which it did do) however when I poured it at the bottom of the bottle I found there was an orange precipitate.

Does this orange precipitate affect the toner? does this mean the toner is finally exhausted? I haven't tried the toner yet on an already untoned print to judge the effect. It didn't do any harm on the sulphide toned print although I would not want it to get stuck to the emulsion.

Also should I just buy more Tetenal or is now the time to try one of the gold toner recipes in the Darkroom Cookbook like Dassonville T-6 or Kodak T-26? Do these have the capacity for long term reuse like the commercial gold toners?

Regards, Simon Grant.

 

[simgrant]

No one has at least seen the orange precipitate before?

 

[Rich Ullsmith]

I have, but not under the circumstances you describe. When sweetening up a pan of toner with a dash of fresh AuCl, it forms an orange precipitant that immediately dissolves.

Gold chloride in it's pure form is crystaline orange, or at least the stuff I have is.

I don't know if the K thio or NH4+ thio exhausts in toner. If you have gotten your money's worth out of your litre of toner, if you have either of these in solution, perhaps add a couple hundred mils of 10% solution and see if the precipitant dissolves. That's all I got.

 

[simgrant]

Thanks Rich, yeah I had heard AuCl was orange. Not sure about what to add to Tetenal Gold Toner though, the MSDS indicates it contains thiourea (thiocarbamide), no mention of thiocyanate. Also, Tetenal is a very long lasting solution, and I have read that gold toner solutions using ammonium thiocyanate have a short shelf life.

 

[Sirius Glass]

Warm it up some and then shake it up well.

 

[Rich Ullsmith]

Now that you mention, seems I remember switching from ammonium to potassium recipe and have not seen that precipitant since. I did not know if the cation in the brew is consumed or goes bad, thought it was just the AuCl that gets exhausted.

With 50+ prints and one liter of toner, you probably got your money's worth, but sure warm it up and shake for a try.

 

[RauschenOderKorn]

I am maybe 15 prints into a bottle of Tetenal Gold Toner and this has happened:



I will try to heat it and dilute the precipitate again. From my count, there should be quite some prints left before exhaustion.

Edit / FYI: I had the pic in the tray and poured the toner directly from the bottle.

 

[RauschenOderKorn]

Heating and stirring will not help. I have heated the orange toner to 60 C an stirred for an hour, no result at all.

The toner goes orange/brown due to some extremely fine precipitate, i.e. the substance causing the colour is not dissolved but a solid. It also accumulates over time at the bottom of the bottle.

Tetenal Gold Toner according to the data available is a "classic" gold toner containing goldchloride and hypo as main ingredients. I suspect (wild guess only !!!!!) the hypo has gone bad freeing up sulfur. So probably some gold (iii) sulphide has formed, which will not dissolve in water any more. Gold (iii) sulphide according to wikipedia is brown, maybe very small particles dispersed in a rather big amount of water can look orange/rusty/brownish.

It does not tone any more and will not dissolve, so silver recovery: here we got some gold for you!!!!