Re: cyanotype toning and staining

[Matti Koskinen <mjkoskin@koti.soon.fi>]

Loris Medici kirjoitti:
> Which paper(s) have you used in your toning trials? IME, some papers are
> more prone to stain with tannic acid + tea always stain much more than
> tannic...
> How heavy is the stain? Just a slight warming or much worse? Is the
> stain in the image area only or does it also stain the non-image area?
>
> Try to rinse/clear the paper thoroughly before toning: wash as usual,
> then clear in 2% citric acid, then rinse again and then bleach/tone...
> Try different papers to see if the stain is more (or less) pronounced
> depending on paper...
>
> I'm sure there will be other useful suggestions other than mine.
>
> Regards,
> Loris.
>   
Hi  Loris,

and thanks. The papers I've been using are Canson Montval, Canson 
Bristol and several no-name aquarelle papers. The staining is quite bad, 
also the other side of the paper is heavily stained. Too strong solution 
of tea? The tannic acid I found was from a winemaker shop, and it has 
distinct strong read colour. Couldn't find tannin, I saw as a kid, when 
my father made his wines, it was pale brownish powder. Might work better 
this variety. Pharmacies used to be places, where strange chemicals 
could be bought, but nowadays all they have is some stuff for food 
preparation. Few years back, I bought potassium dichromate from a 
pharmacy, luckily quite a lot of it, and still have the other container 
un-opened. Cyanotype chemicals e.g can't be get any more, have to use a 
ready cyanotype kit. (which is the only alt-proc kit available here in 
Finland)

What are the regulations concerning mailing chemistry from abroad? In 
Great Britain are other alt kits availabe and then there are companies 
in the U.S. But are these substances so hazardous, they can't be mailed?

thanks

-matti