[alt-photo] Re: Speedy Cyanotype Question LONG POST

Mon Apr 12 15:07:34 GMT 2010

Thanks Chris.

I am definitely archiving this information.

-francis

On Fri, Apr 9, 2010 at 11:46 AM, Christina Anderson <zphoto at montana.net>wrote:

> Francis,
>
> I learned lots from Sam Wang about cyano. He was so good with that process.
>  I've got his cyano chart somewhere, of the different formulations graphed
> out.
>
> By increasing the FAC to 2:1 with the 20% FAC and 8% PF I find it about a
> stop difference in time and I think Sam might agree, but he's in China
> basking in his huge show right now.
>
> We had a great discussion a while back with Alberto Novo chiming in.  I am
> cutting and pasting notes I have saved on this topic--since this was on the
> list and is still the list.  It was just too good of a convo to pass up.  It
> is NOT organized so you will have to realize what was said in what order,
> but it may answer some interesting questions for you.  But if grain is not
> your issue, then maybe all the below is not necessary to the shoe project.
>  But I'd file it anyway...because it's good stuff, why this list is so
> useful.
> Chris
> PS Hope you're coating the shoes carefully--I apparently had spilled some
> cyano wash water down the side of my cabinet in my bathroom and didn't
> notice it until over the course of the last several months I've now got a
> Jackson Pollock blue vanity :)
>
>
> >From the alt list:
> I don't believe anymore that there is a traditional or classical cyanotype.
> Here are the compositions in g/100 ml in sol A:B and their ratios, gathered
>  from different
> sources: 12.5:4.5 = 2.78 Wall (Photographic Facts and Formulas, 1924) 24:7
> = 3.42 Namias (Chimica Fotografica, 1929) 36:16 = 2.25 Clerc (La Technique
> Photographique, 1950) 25:12 = 2.08 Glafkides (Photographic Chemistry, 1958)
> 22:15.4 = 1.42 Nettles (Breaking the rules, 1977) 25:25 = 1.00 Frederick
> (Creative Sunprinting, 1980) 20:8 = 2.5 Barnier (Coming into Focus, 2000)
> Note that the ratio 25:12 (Glafkides) is very close to the optimal ratio Fe
>  am. citrate/ferricyanide which gives themaximun yield in Prussian Blue.
>  Higher values (an excess of fe am citrate over ferricyanide, requested for
>  the formation of Prussian blue) give more sensitivity but also bleeding.
>  Lower values (an excess of ferricyanide) give no bleeding, lower
> sensitivity  and more contrast. DMax is proportional to the amount of
> Prussian Blue, so I
> suggest to choose  a formula with a ratio equal or lower than 2.08,
> possibly increasing the  overall concentration. Cyanotype is also very
> sensitive to alkalinity in the  paper
> (most of them are buffered with calcium carbonate) and in the water,  so a
> first soaking (not more than 30") in acidic water is higly recommended.
> Alberto
> Not against the mottling (it might depend on the internal sizing of
> Plaine), but against bleeding and staining: try increasing the amount of k
> ferri, for example using a 1A:1.25B ratio or more (or less than 0.8A to 1B).
> You will also have a little more contrast and longer exposure times.
> Alberto
> My interest in the bleeding was wondering if the FAC was the culprit, if
> its molecules are the bigger ones that maybe don't sink in as well into the
> paper fibers, because it is the increased FAC that bled.
> There is an interesting patent on blueprints, cited also by M. Ware but not
> deeply enough IMHO (Crawley et al., US 2,350,991), where the author
> speculates about bleeding / non bleeding formulations regarding their ratio
> of (light-sensitive ferric compound)/(iron cyanide compound). For ratios
> above 2 (that is, an excess of light-sensitive iron) bleeding occurs due to
> a lack of reacting iron cyanide (this patent deals with mixtures of ammonium
> iron oxalate and potassium ferri- and ferro- cyanide).
> Ammonium iron citrate (green) is given with an iron content ranging from
> 14.5 to 16% as Fe.
> My calculations are that, for a 10% potassium ferricyanide, the
> non-bleeding equivalence would be a solution of ammonium iron citrate
> (green) between 20 and 23%. If so, 25% is in the bleeding range.
>
> My experience is that, despite the enhanced exposure times due to the
> filtering effect of ferricyanide, a lower concentration of am fe citrate (or
> an higher concentration of k ferricyanide up to 1:1 to am fe citrate) gives
> no bleeding, deeper blue and contrasty images than the usual 10:25 (K ferri
> : am fe citrate) formula.
>
> As for the effect of the acid washing, I have noted an increasing staining
> of highlights leaving the prints in acidified water for more than 10-20".
>
> Ware himself recommends a "half a minute in very diluted hydrochloric or
> nitric acid" (10 cm3 to 1 litre  water)" ("Cyanotype", pag. 107) and that "a
> lesser dilution of a more diluted stock solution of acid may be preferred".
> Also, "These [acid] developments baths tend to accumulate Prussian blue,
> which will eventually begin to stain the paper" (p. 108).
>
> BTW: I have noticed a very different behaviour between 300 and 600 g/m2
> Fabriano Artistico, the latter giving deep blues and contrasty prints than
> the former. I don't know if this is due to a different absorption or a
> different sizing.   Alberto
>
> AHA Alberto,
>
> This is exactly what I am looking for.  My formula is 20%A to 8% B thus a
> 2:1 is 40%A: 8%B, so by your calculations, anything above using a .92A:1B
> would promote bleeding--even 1A to 1B would do so, which is what I find in
> practice.
>
> My guess was always that there was too much of SOMETHING in the formulation
> that created the runoff, but I never knew what the "something" was until I
> saw how smooth and non-bleeding the side by sides were with increased
> potassium ferricyanide.  But I wasn't sure I could trust my eyes nor did I
> know the chemistry reasoning behind the observation.
>
> In Ware's book he defines an average of the two as being a 26% A to a 12% B
> which would also follow your guess, below--being the most of A that might
> work with B without bleeding.  It would equiv to your formula of 21.6%A to
> 10%B, comparing apples to apples.  Thanks for this tidbit, it really
> clarifies things for me. Maybe an unrelated question--is it **possible**
> that the bleeding in pt/pd could similarly be caused by an excess of iron?
> Chris
>
> My calculations are that, for a 10% potassium ferricianide, the
> non-bleeding equivalence would be a solution of ammoniium iron citrate
> (green) between 20 and 23%. If so, 25% is in the bleeding range.
>
> My experience is that, despite the enhanced exposure times due to the
> filtering effect of ferricyanide, a lower concentration of am fe citrate (or
> an higher concentrtion of k ferricyanide up to 1:1 to am fe citrate) gives
> no bleeding, deeper blue and contrasty images than the usual 10:25 (K ferri
> : am fe citrate) formula.
>
> The explanation why an excess of "reactive iron" to "color-forming iron"
> (i.e. K ferri) produces bleeding would be that the reacted iron moves from
> its original position faster than the K ferri reacts with it.  So I second
> that this would apply also to other iron processes, substituting the
> "color-forming iron" whith whatever reacts with the photochemically formed
> iron(II). The calculation have to be made with moles and not grams. Note
> that am fe citrate is the only poorly defined substance (a 14.5-16% Fe).
> Alberto
>
> I don't believe anymore that there is a traditional or classical cyanotype.
> Here are the compositions in g/100 ml in sol A:B and their ratios, gathered
> from different sources:
>
> 12.5:4.5 = 2.78 Wall (Photographic Facts and Formulas, 1924)
>
> 24:7 = 3.42 Namias (Chimica Fotografica, 1929)
>
> 36:16 = 2.25 Clerc (La Technique Photographique, 1950)
>
> 25:12 = 2.08 Glafkides (Photographic Chemistry, 1958)
>
> 22:15.4 = 1.42 Nettles (Breaking the rules, 1977)
>
> 25:25 = 1.00 Frederick (Creative Sunprinting, 1980)
>
> 20:8 = 2.5 Barnier (Coming into Focus, 2000)
>
> Note that the ratio 25:12 (Glafkides) is very close to the optimal ratio Fe
> am. citrate/ferricyanide which gives the maximun yield in Prussian Blue.
> Higher values (an excess of fe am citrate over ferricyanide, requested for
> the formation of Prussian blue) give more sensitivity but also bleeding.
> Lower values (an excess of ferricyanide) give no bleeding, lower sensitivity
> and more contrast. DMax is proportional to the amount of Prussian Blue, so I
> suggest to choose a formula with a ratio equal or lower than 2.08, possibly
> increasing the overall concentration. Cyanotype is also very sensitive to
> alkalinity in the paper (most of them are buffered with calcium carbonate)
> and in the water, so a first soaking (not more than 30") in acidic water is
> higly recommended. Alberto
>
> Christina Z. Anderson
> christinaZanderson.com
>
> On Apr 9, 2010, at 2:16 AM, John Brewer wrote:
>
> > Hi Francis,
> >
> > The dichromate is a highlight restrainer and the oxalic acid I believe is
> > insurance against slightly basic paper.
> >
> > John.
> >
> >
> >
> >
> >
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-- 
francis schanberger

www.frangst.com