Re: New Cyanotype - my first unsuccessful attempt

From: Scott ^lt;[email protected]>
Date: 08/19/04-07:38:12 AM Z
Message-id: <004301c485f1$c605d4e0$>

Hi Loris -

> Do you or anybody else know what is the life of solution (or coated paper)
> when one adds citric acid in it? My practice is to add 2 drops per ml of
> sensitizer (1ml = 24 drops, 2 drops ~= 0.08ml) BTW.

I only add the citric acid to the sensitizer just before coating but I do
remember Dr. Ware saying he would not advise adding it to the stock
solution. As for coated papers, I only coat and expose 1 at a time. The one
time I kept coated paper for 24 hrs it turned blue but I can't remember if
it was Dr. Ware's formula or a traditional on or if I added citric acid to

> Oops! Then I definitely won't clear in citric acid - I sell prints
> and I absolutely don't want them to fade in normal display conditions.
> can you say about citric acid addition into the sensitizer? Can this
> the longevity of the print in the same way?

My feeling is that a nitric or hydrochloric bath would remove the citric
acid from the print but I am not a chemist. What effect it has on the
longevity of the print I have no idea.

> Ok, then nitric acid is the way... Well, that's nasty! I have dealt with
> concentrated sulfuric acid but not nitric - I guess it's nastier than
> sulfuric (more toxic fumes? My concentrated sulfuric didn't fume much, if
> not at all)...

Yes it is very nasty. More so than hydrochloric acid. But like I said I have
a couple of liters on hand so i'm using it up.

Regards, Scott
Received on Thu Aug 19 07:43:39 2004

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