Bob Carnie
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Bob, I gave you the answer 3 years ago
alpha-Napthol is a blue colour coupler, details and link on APUG
Ian
I need a cold toner that is permanent for the shadow areas. The results I have now are what I like but the blue end is not permanent and over time will fade, the silver will still be there but I am hoping to find a solution to this.
I am using a two bath dev for the solarizations and am Bleach Sepia for the highlights, Gold * peach tone* for the upper midtones and iron blue for the shadows.
Bob, I gave you the answer 3 years ago
alpha-Napthol is a blue colour coupler, details and link on APUG
Ian
Bob, in what way do you consider the iron blue toner, which creates the Prussian Blue pigment also typical for Cyanotypes, not "permanent"? I know cyanotypes can have a tendency to bleach a bit under light, but this is largely reversible by dark storage and access to air. In addition, the issue seems quite diverse, and possibly related to impurities of remains of sensitizer in cyanotypes (not present in your blue toned images), see Mike Ware's documents about this.
Overall, cyanotypes seem not to bad in terms of "archivability", and I don't really see how a dye based toner would improve over it, considering the reputation of non-reversible fading of color photos in general?... Prussian blue is also a well regarded oil painting pigment, although admittedly, oil paint layers are of a different order in terms of thickness and amount of pigment present.
Lastly, even Tim Rudman, has used blue toner in some of his remarkable images (I like yours by the way!)
Marco
As you may gather, I am a printer and not a chemist. To my thinking if the dye can wash off then its not like the sepia , gold or even selenium in the way it works.
It sits on top of the paper as a stain and to my thinking suspect.
I need to think this over as I really prefer the ironblue in the shadows over selenium.
Bob, iron blue, or better said the Prussian Blue pigment that forms its color, can indeed wash off. The process is called "peptization", and differs from dissolving for example sugar in water, in that a solid (the colored pigment) gets washed away with the water, instead of getting dissolved like sugar or salt in water. It is equivalent to washing the sand of your boots after a walk on the beach... The problem here is that the colored pigment like you rightly concluded doesn't really bind to the paper or gelatine in any really reliable way.
You are also right iron blue toner is unlike sepia and selenium toning. The big difference with sepia and selenium is that these last toners chemically react with the silver in the photo paper's gelatine layer, and form a strong molecular bond, that is, the toners components (sulphur for sepia, selenium for selenium toner), directly bind with the silver, much like oxygen and water bind with iron when it rusts. No way you wash this off the paper (unless you melt the entire emulsion layer of the paper), just like you can't wash off rust of the steel hull of a ship...
However, as you can see, the "peptization" of iron blue, requires water (and lots of it). This essentially means your toned image is "safe" from degradation or loss of image color, as long as you do not wash it again after it is toned, (briefly) washed according to toner instructions, and subsequently completely finished and dried.
But why would you want do that?
So, all in all, I would say: don't worry about it! It is safe to use the iron blue toner, as long as you can get the results you want.
The only additional advice I can give you, is to do any proper archival washing before the iron blue toning (meaning that one should go last in the toner usage sequence), and keep washing of the iron blue toned print to a minimum, to avoid washing away to much of its color.
Marco
I am very happy with the look therefore I think my quest is over.
Now start making the prints and exhibiting
Keep your ears open as these prints may be coming to a gallery near you.
Yes, the look is great, I especially like the left one with bicycle crank, but they are both beautiful in this "finish". Go for it!
Cyanotypes have survived from the dawn of photography, and that is longer than most colour C-prints will...
Ah well, the crank I guess is a give-away... must (well, almost) have been shot in the Netherlands
Anyway, post any exhibition dates and places here if you know anything definite.
Bob, it's a problem of "tooth;" gum needs some fiber or texture or something for the hardened gum to attach to, or it will slide off the surface during the development wash. If the new paper is like a rag paper, maybe there's enough tooth there for gumover; that would be pretty exciting.
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