[alt-photo] Re: HYDROSCOPIC!

[Loris Medici]

Bob,

1. Why don't you try gold-thiourea? It's easier to use (toner is mixed
once and keeps pretty well), plus, the action is very uniform
(non-proportional) and fast.

2. Just a speculation: Solubility information says 128g in 100ml (0
C). Learn solubility at room temperature (or other temperature that is
practical for you) and mix a saturated solution. You'll then know how
much dry equivalent you have in the top (more liquid) half...???

Regards,
Loris.


2010/5/10 BOB KISS <bobkiss at caribsurf.com>:
> DEAR LIST,
>
>            Can anyone help me with the following?
>
>       I want to mix some Ammonium Thiocyanate gold toner.  Bloody Ammonium
> Thiocyanate is seriously hydroscopic.  The sealed plastic env in the B&S
> toner kit is liquid!  No problem here because it is premeasured to make a
> small amount of toner.  However, the local university which is happy to get
> rid of their supply has two 500g  bottles of Ammonium Thiocyanate that are
> both liquid!!!  No one can say for sure if any has been taken from the jars
> so no way to be certain of the concentration.
>
>            I see no reason I can't use these liquid Am Thio solns from the
> bottles but I need to know when I have added enough per liter for the toner.
> I am betting that all these alkaline salts (Borax, Amm Thio, etc.) are
> mainly to set the pH for the gold toner which determines the resulting
> particle size and hence color.  Might it be possible to determine the
> correct pH in the liter of the alkaline soln and simply add the soln from
> the bottle to, let's say, 800 ml of distilled water until it reaches that
> pH?  Adjust vol & more Amm Thio to 1 liter at the correct pH?
>
>            Of course, the trick question is, what IS the correct pH?
>
>
>
>            The formula from Chris James' book is:
>
>
>
>                        800 ml dist water
>
>                            25g  Ammonium Thiocyanate
>
>                              2g  Tartaric Acid
>
>                              5g  Sodium Chloride
>
>                          20ml 1% gold chloride soln
>
>
>
>            Any ideas?
>
>                        CHEERS!
>
>                                    BOB
>
>
>
> _______________________________________________
> Alt-photo-process-list | http://altphotolist.org/listinfo
>