platinum toner shelf life

[davido]

hello

I've been toning my Vandyke's with platinum. I mix up a litre of the toner at a time and then use it as a one shot.
I've noticed a very slight tone to my highlights. It's almost barely there but it concerns me. I am trying to find the culprit and wondering if using toner which was made last summer might be at fault?
I do remember reading somewhere that platinum toner does have a shelf life but what happens after that? Does is merely just loose strength or could it have a staining tendency.

cheers
david

 

[Jim Noel]

If you are getting a color cast in your highlights look somewhere other than the toner. Is this really platinum or is it palladium? Either will last an awfully long time if you mixed with distilled water. My palladium toner is more than 2 years old and shows no signs of aging.

 

[davido]

Thanks Jim.
It is platinum. I have both and prefer the platinum.
I'm just trying to narrow down this colour cast. Christopher James in The Book of Alternative Processes says that distilled water must be used as the initial water bath (with citric acid) because " there might be chlorine in the water supply. . . and this is a powerful oxidant.If the silver oxidizes during this stage, highlights will often turn a light coffee tan."
I will try the distilled and see if that makes a difference.
Of course it also could be that the ferric iron is not all being removed in the clearing and wash. I am clearing in three separate water baths (with citric acid) and then washing for a few minutes in running water, for a total of around 15 minutes. Also, I am doing two coats of sensitizer, which can also be problematic but I find necessary for good dmax.

david