[alt-photo] HYDROSCOPIC!

[BOB KISS]

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