Re: New Cyanotype

Judy,

When you say the emulsion is too fresh, you said this is the A & B themselves. By this I assume you mean that A & B should be mixed and then let the bottles sit on the shelf for at least 3-4 days and not use them immediately. True?

I live in the Boston area and get my water from the Boston water system, which eventually comes from the Quabbin reservoir in the middle of the state. When I first started doing cyanotypes (traditional formula), I found that they looked great when they came out of the wash water and then the next morning when they were dry, the image was mottled and largely bleached out. On researching the Boston water, I found on their web site that

"MWRA now treats the water at the Interim Corrosion Control (ICC) facility with sodium carbonate (soda ash) and CO2 (carbon dioxide) to increase the pH and buffering capacity of the water. This has considerably reduced lead levels found when you first use your tap. Bi-monthly pH results are available in the Update. "

The MWRA also reports elsewhere that they have a target pH of 8.8 to 9.4 (http://www.mwra.com/monthly/wqupdate/pdf/wq2004apr20.pdf)

Following suggestions I had read on this list, and consulting with a chemist friend, I now add about 5 ml of 5% HCl to 2 liters of rinse water to neutralize the buffering. (I could easily use other acids, but I had 1 gal of muriatic acid for some toning experiments.) I find that my wash water is now ALWAYS deep blue, but my images are also a deeper blue, and they don't fade away on me. I am slowly experimenting with reducing the amount of acid. Also, my solutions have been sitting on my shelf for a few weeks, so it is not the case of them being too "young".

--
Bill Leigh
wrleigh@att.net
> 
> 
> On Tue, 18 May 2004, Christina Z. Anderson wrote:
> > The complaints about the traditional (old) process are that it is rather
> > slow, the ammonium iron citrate grows mold easily, the sensitizer does not
> > often absorb into paper well, the Prussian blue is soluble and washes out
> > during wet processing, and stained highlights are quite common because
> > excess ferrous iron in heavily exposed areas diffuses out into the
> > highlights.
> 
> Christina, I notice that you say "the complaints about the traditional
> (old) process are....", but you don't say you have observed these things
> yourself.  I have made hundreds of cyanotypes, and taught airhead
> undergraduates who must in the aggregate have made thousands more-- and
> NEVER seen the Prussian blue wash out during wet processing except in two
> circumstances:
> 
> 1. When the emulsion is too fresh..  I don't mean A&B freshly mixed
> together, but when the A & the B themselves have not aged enough. I found
> that two hours old they washed off about 60%, after that they washed off
> successively less.  Until about day 3, or maybe 4, no washing off.  That
> is, no "blue water." However, the top visible step of a freshly exposed
> but not yet developed print does drop down 2, or 3, or more steps in
> development. I don't know if New Cyanotype does that, but you can easily
> allow for it in exposure. (And that makes green not blue water.)
> 
> 2. When the paper is not absorbent enough or too much emulsion is sloshed
> on. Look at the freshly coated paper at an angle -- if you see puddling,
> it will wash off after exposure, often leaving white spots.
> 
> Perhaps alkaline wash water has this effect, but I do not believe it is
> intrinsic to the medium.  I have also NOT seen those "stained highlights."
> except where the negative was too thin.
> 
> Judy