[alt-photo] Re: post fixer toning of VDB

[Loris Medici]

  Ok, then:

1- The print out is due to humidity in the paper and the intrinsic 
nature of the sensitizer
2- There isn't any latent image
3- The image darkens (in processing) because of silver grains change 
size (aggregate?) and/or shape
4- The image further darkens when the paper gets dry and shrink, because 
silver grains further aggregate

Thanks & regards,
Loris.


16.07.2010 23:22, Alberto Novo yazmış:
> Loris,
>> OTOH, I really don't undestand what's going on with Vandykes; you 
>> expose, you get a print out image (which is considerably weaker than 
>> its fully processed / final state), and you tone/fix or fix, and the 
>> image considerably darkens. What's happening in between? Perhaps the 
>> paper has both a silver image and a latent image before fixing, is it 
>> indeed so?
>
> The first (POP) image is due to the humidity carried by Fe Am citrate: 
> in absence of water there are no ions that could react among them. 
> This holds for all the processes without a true latent image. See for 
> instance the difference between platinum print and ziaype, this last 
> with litium or ammonium salts, and the different results varying with 
> different humidities.
> For the following Terry gave you the answer.