Blue Toning problem

[David Lingham]

Could I ask for help with a toning problem please. This afternoon I attempted to duo tone a few prints. They are all made a couple of days ago on Adox MCC 110 processed in Ilford PQ with a two bath Hypam fix followed by an hour in a slot washer. My usual toning procedure is as follows. After a pre-soak, a brief selenium tone, 90 sec @ 1+12. Then wash for 20 mins, followed by 90-120 secs in a homemade Iron blue toner, Ferric Ammonium Citrate, Potassium Ferricyanide and Succinic acid. This toner is used at a very weak dilution from the stock solution. Finally a clearing wash in a salt water bath, which is a teaspoon of table salt to 1 litre of water. I’ve used this procedure a number of times with consistency and without failure. However, when two of the prints were put into the salt clearing bath, the hi lights started to bleach away. Not only the blue toner but the silver image as well. And I can’t think why.

 

[TheToadMen]

I haven't got a clue. And when I don't I try to trace my steps and double check all ingredients. What did I do? Where there any deviations or did I forget a step or did I use a new brand/type of something?
Did I use a contaminated device, like a tray used before to bleach and that wasn't cleaned, or did I use a wrong concentration of an ingredient, or did I put bleach in a can I normally put distilled water in, or ...
If not, I try to reproduce it by replacing one factor (cleaned tool, fresh ingredient) at a time, starting at the end of the process, thus eliminating an unknown error.

Good luck hunting!!!

 

[tkamiya]

I've played with blue toner a bit.

Apparently, toner's ability to "blue" the print expires long before ferri stops working. So when I used very dilute toner, it bleached print after toning effect stopped.

 

[David Lingham]

Thank you both for your replies. It's strange it only happened with 2 out of the 6 prints I toned. I'll double check everything, all I can think of is those 2 prints hadn't washed correctly.

 

[Rudeofus]

My guess would be that the salt bath got contaminated with Ferricyanide which bleached away both the Silver image and possibly also the blue toned image parts. Since salt is Sodium Chloride which can dissolve Silver ions, there is a chance that salt + Ferricyanide formed a BLIX.