Re: Merits and Demerits of Salted vs. VDB

[Gordon Cooper <nwlorax@comcast.net>]

Sandy King wrote:
> At 9:16 AM -0600 9/1/07, Christina Z. Anderson wrote:
> > However, in my packet of step wedges and test prints and tonal 
> > palettes printed in both, I notice that there is a fading and 
> > yellowing and mottling in the VDB packet I do not see in salt. The 
> > salt prints look exactly like they did the day I made them.  In the 
> > troubleshooting section of my VDB chapter (Alt Proc Condensed) I have 
> > a quote from Mike Ware via Wynn White: "Most sources state that 
> > Vandyke prints can be cleared in plain water.  In Mike Ware's 
> > description of the argyrotype process he explains the problems 
> > iron-based silver processes have.  If processed in an alkaline 
> > solution residual ferric iron is left in the print which will 
> > eventually cause it to fade since iron (III) will oxidize silver."
> >
> >
> > Chris
>
> There are two important steps that if carried out will dramatically 
> improve the quality of VDB prints. The first is to make absolutely 
> sure that the first wash is carried out in water that is slightly 
> acidic. If the water is alkaline iron hydroxide will be set in the 
> paper and this can can be removed in subsequent processing. However, 
> don't make the first bath too acidic because it might bleach the silver.
>
> Second, bite the money bullet and buy some noble metal solution (gold, 
> pallaidum or platinum) and tone the print before fixing. This will 
> eliminate bleaching and give you the deepest possible shadow values.
>
> Sandy King
I use a platinum toner after an acidified wash. An important factor is 
the quality of the rinse water My apartment's water supply is through 
50+ year old steel pipes. I have had bits of iron from this stick to my 
VDB papers while rinsing. I have gone to the use of distilled or 
de-ionized water for all of my process steps. Expensive, but consistency 
counts for a lot.


Gordon Cooper
Bremerton, WA