Re: report on cynotype and acid and a chemistry question.

Dear Tom,
Sorry I took so long before answering your message,
I've been teaching 10 hours days the last 3 days and
my mind is in another planet...
No, your question was not unclear, I am just tired...
My stock solution is: 100 grams of ferric ammonium
citrate to 500 ml of water and 40gr of potassium
ferric cyanide to 500ml of water.
II am doubling the ferric citrate, because my printing
times were very long and Christina suggested for me to
do that. I believe that she has been using cyano this
way for tri-color gum. Since she is so knowledgeable
and helpful, I believe that she will have a much
precise answer for you.
Combining the chemicals this way and with the addition
of the citric acid, works for me; (better contrast,
d-max, tonal rage and shorter exposures) but I read
somewhere, I think it was the Christopher James book
that doubling the Ferric citrate could cause bleeding
of the shadows...
Let me know how it works for you, if you decide to try
it,
:-)
Carmen

--- "T. E. Andersen" <postlister@microscopica.com>
wrote:

> Thank you Carmen,
>
> It seems my question was a bit unclear. I meant the
> actual recipe. Am I
> to understand that you use these amounts of
> solutions containing
> "standard" concentrations of the two chemicals (i.e.
> something in the
> order of ~25% ferriammoniumcitrate and ~12.5%
> potassiumferricyanide in
> the stock solutions)?
>
> If I have understood this correctly, my next
> question is: Why are you
> doubling the amount of ferriammoniumcitrate?
>
> Tom Einar
>
>
>
> Carmen Lizardo wrote:
> > Tom, I used 20ml of ferric ammonium citrate
> solution,
> > 10ml of potassium ferric cyanide and 5 ml of
> citric
> > acid.
> > I diluted 40 grams of citric acid in 100ml of
> > distilled water.
> >
> > Carmen
> >
> >
> >
> > --- "T. E. Andersen" <postlister@microscopica.com>
> > wrote:
> >
> >
> >>Hello Carmen,
> >>
> >>Thank you for the information on using citric acid
> >>in the cyanotype
> >>sensitizer.
> >>The information you give about your recipe puzzles
> >>me a bit. Could you
> >>please post your actual recipe? The one I've
> always
> >>used, as well as all
> >>other that I have checked, use a 1:1 ratio of the
> >>two component
> >>solutions. This implies that you may have a
> >>significantly different
> >>recipe from what I'm used to.
> >>
> >>Also,- when you say 25% citric acid, what do you
> >>mean? Is it 25% of the
> >>total volume? 25% by weight of citric acid in the
> >>final solution?
> >>
> >>Thanks again, and have a fine day!
> >>
> >>Best regards,
> >>Tom Einar Andersen
> >>
> >>
> >>
> >>Carmen Lizardo wrote:
> >>
> >>>I used the classic formula, mixed 2a: 1b and
> added
> >>
> >>25
> >>
> >>>percent of citric acid (Of a 40 percent solution
> >>
> >>of
> >>
> >>>citric acid mixed with distilled water).
> >>
> >
> >
> >
> >
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>

        
                
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Received on Thu Oct 27 19:49:11 2005