Re: New Cyanotype - my first unsuccessful attempt

Joe, this sounds good to me...

Richard, I deleted your post and then I wanted to ask you a question about
it (darn) but I think it is this: what is a "sequestering" agent?

Oh, why oh WHY did I avoid chemistry in high school and college???
Chris
PS This is SOOOO off topic, but I had to share--I had a SCORPION in my house
last night! I heard these things were down here in the south but this was a
first live sighting. Needless to say I'm a bit freaked. No, I didn't
photograph it.

----- Original Message -----
From: "Joe Smigiel" <jsmigiel@kvcc.edu>
To: <dickburk@ix.netcom.com>; <alt-photo-process-l@sask.usask.ca>
Sent: Thursday, August 19, 2004 8:39 PM
Subject: Re: New Cyanotype - my first unsuccessful attempt

> I don't recall the original poster's message, but I might suspect the
> issue has something to do with the paper and buffering. Perhaps the
> nitric and sulfuric acids, being stronger, are more efficient at
> removing any buffering agent in the specific paper being used. The
> weaker citric acid may just not be strong enough to keep the paper
> acidic and so fading occurs and is accelerated compared to the other
> flavors.
>
> At one point in the discussion someone mentioned being able to print on
> butcher's paper and it sounded like they were almost surprised at this.
> IME, printing on very cheap papers such as that mentioned (and paper
> bags, unbuffered papers, etc.) with the cyanotype process is easily
> accomplished. It is the higher quality artist's papers, especially
> those labelled "acid-free," which are difficult to make a good blueprint
> upon.
>
> All this is just a guess on my part but perhaps one of the chemists on
> the list could relate the relative pHs of the various acids mentioned
> and whether a particular choice might adversely influence the fading of
> the image as well as the longevity of the paper substrates.
>
> Joe
>
>
> >>> Richard Knoppow <dickburk@ix.netcom.com> 08/19/04 5:04 PM >>>
>
> ----- Original Message -----
> From: "Scott Wainer" <swphoto@verizon.net>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Thursday, August 19, 2004 1:07 PM
> Subject: Re: New Cyanotype - my first unsuccessful attempt
>
>
> > It may have to do with the chemical structure of the new
> formula. As Dr.
> > Ware points out in his book on cyanotype, the new formula
> forms a lattice
> > structure that can hold and bind other chemical molicules.
> It may be that
> > citric acid is retained and reacts with the chemistry or
> the paper over a
> > period of time and causes fading. Nitric and hydrochloric
> acids might not be
> > retained as strongly as citric acid and therefore cause
> less fading. I am
> > not a chemist so this is all conjecture on my part.
> >
> > Scott
> >
> >
> Well, I am NOT a chemist but Citric acid is a well known
> sequestering agent so that might have some effect. Just a
> guess. Lemon juice works well for cleaning mineral deposits
> off pots and kettles, perhaps it also has an effect on
> metals. In any case Citric is an organic acid and the others
> are not, perhaps irrelevant.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@ix.netcom.com
>
>
>
>
Received on Fri Aug 20 06:26:25 2004