[alt-photo] Re: Platinum toning a Kallitype

[Alberto Novo]

Matteo, 

> I read you can make a Kallitype platinum toner in a few different ways: each recipe I've found though calls for potassium chloroplatinite... I personally bought Potassium tethrachloroplatinate: can I just substitute it for the "ite", or are they quite different compounds?

The chemistry of the toner is:
2 Ag + K2PtCl4 --> 2 AgCl + Pt + 2 KCl (chloroplatinITE)
4 Ag + K2PtCl6 --> 4 AgCl + Pt + 2 KCl (chloroplatinATE) 

Hence, if you tone with Pt(IV) you have an overall loss of density (that is, 
also in the shadows) of about 1 stop that you cannot counteract 
overexposing. 

Alberto 

www.grupponamias.com
www.alternativephotography.com/articles/art102.html