ooooooooon the other hand, I don't think i'll share photographs of my toned images. My tanic acid is still way to strong and basically destroyed the print with stain. I need to try a citric acid bath post development and see if that reduces my stain and still gives me a good brown. I suppose worst case is I buy 2 part sepia toner
I'll give that a go mooseontheloose when I start using real paper again.
I've toned some in simple green tea with really interesting results. It turned violet which i didn't expect, but i kinda like it. I think i can put an example up sometime today.
edit: here's the pic
Shame the scan isn't really good. The print itself looks much better.
Last edited by noeffred; 06-19-2010 at 08:38 AM. Click to view previous post history.
I had trouble with cyanotype washing away down the sink so I can sympathise! I wanted to know what was causing it so devised a set of experiments that controlled the chemistry of the wash water, the paper and the sizing. Primarily my results showed that it was the acidity/alkalinity of the wash water that controlled the 'colour' of the blue: with acidic, the colour is a classic 'cyan', with alkaline, the blue goes more to a steel grey. With more alkaline development (ph 7+) there is a very slight bleaching effect of only lightly exposed regions, resulting in a higher contrast and apparent slower speed. With more acid development, the bleaching does not occur and so gives the impression of lower contrast and faster speed. If the paper is very acid or very alkaline, it can influence the wash water too (I have made papers ranging from pH 2 to pH 13 as part of my experiments); I had one water colour paper that was pH 9 and when I developed in mild acid, I had very little washout and great fine blue tones, but as the water evaporated and the print dried, the alkalinity of the paper bleached out the fine tones back to white and the contrast appeared to increase.
If there are impurities in the paper that are incompatible with cyanotype (not sure what the impurities are, I just know some papers have them), then the paper will fog if you leave it too long before exposure: a simple test is to coat a sheet of paper and leave it in the dark without exposing it. If it is still the same pale yellow colour after a week, your paper is 'cyanotype friendly'. Some modern watercolour papers I tried showed some darkening to a green/blue tint of the unexposed paper after even a day or so which is a little worrying.
The sizing used in the manufacture of the paper determines how well the sensitiser sticks and correspondingly, how much washes off in development, and therefore the final achievable Dmax. Paper that has size that prevents the sensitiser sinking in, as Loris noted, is far more prone to washout. If you alkaline develop, the fine wash-out particles seem to bleach rapidly so when they re-attach, they are not noticeable. With acid development, the free Prussian blue particles stick to anything and everything! Some sizes also seem sensitive to acid development and although the Prussian blue begins to wash out with water development, sometimes acid seems to make the size more porous and so capture the blue at the point it starts to wash away. I had one paper that worked well in this respect when I developed it in weak hydrochloric acid; it was rather disconcerting though as the paper fizzed in the development bath as the alkali buffer was reduced too! The images often looked slightly blurred when this process had occurred, suggesting a localised re-attachment of the blue. A coat of 3% gelatine as a surface sizing can help reduce wash-out and make many papers very usable.
Best regards, and most of all, have fun!
Evan and others: a few points:
- First, the Prussian Blue pigment, just like many Ferricyanide pigments, isn't stable in alkaline environments, worse, it will be destroyed. Developing in alkaline water is bound to be a failure, just like having a heavily alkaline (calcium carbonate) buffered paper leads to bad results.
- But not only the end product of the reaction, the blue color, is sensitive to alkaline conditions and OH- anions. The speed increase in vinegar is probably due to the fact that you are creating the more or less "ideal" environment for the iron sensitizer. The iron sensitizer is the stuff that is light sensitive and reacts when you expose it. If, due to alkaline conditions, part or all of the iron sensitizers is destroyed by what Mike Ware describes as "Hydrolysis", where the iron and oxalate bond of the light sensitive substance is broken down, than you loose exactly that component that is supposed to form your picture by reacting with light and subsequently, in case of the Cyanotype, with the Ferricyanide anion.
From one of Mike's documents:
The iron(III) complex is photodecomposed to give iron(II):
Light + 2[FeIII(C2O4)3]3– ---> 2[FeII(C2O4)2]2– + C2O42– + 2CO2
The complex iron(II) photoproduct is in equilibrium with the aquated ferrous ion:
[FeII(C2O4)2]2– ---> Fe2+(aq) + 2C2O42–
and this then reacts with the ferricyanide anion to precipitate the highly insoluble substance, Prussian blue:
Fe2+(aq) + [FeIII(CN)6]3– ---> FeIII[FeII(CN)6]–
It is the bold substance, which is your sensitizer and that will (at least partly), hydrolyse in alkaline conditions, leaving your paper less sensitive. The bold/italic substance is the Prussian Blue, which is also sensitive to alkaline conditions.
- I recommend you all to read Mike Ware's excellent documents on Cyanotype and Iron based processes in general. Well worth the read, especially if you have some basic knowledge of chemistry of your schooltime left... Start with:
* Chemistry of the Iron-based Processes
Than, if you feel up to it:
* A Blueprint for Conserving Cyanotypes
And maybe also:
* The New Cyanotype Process
- When you teatone, you have (free) iron react with gallic acid, to create a classic new pigment, also known as Iron Gall ink, a dark blueish/purplish/black pigment that has been used as ink since the end of the middle ages, but was even known in antiquity.
"The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true.
" - William M. Ivins Jr.
"I don't know, maybe we should disinvent color, and we could just shoot Black & White.
" - David Burnett in 1978
"Analog is chemistry + physics, digital is physics + math, which ones did you like most?
Evan you made me think and change my process a bit and what can I say? Success! I've noticed that the paper tends to fizzle in the vinegar mix which would be an indicator of an alkaline buffer. So in order to make it more Cyanotype firendly, I soaked the whole sheet in 1:1 vinegar until the sheet stopped fizzling. I hung it to dry overnight and just did some exposures which are drying as I type.
There is now virtually no run-off at all when I develop it in vinegar (same goes for water as far as I could see) and the tonal range as well as the blues seem to be developing pretty nicely (prints are still drying), I can only advise you to give that a go!
It seems to me that all my papers have a buffer in them, they all fizzle in the vinegar
btw: someone should make this thread sticky. I think we've got some good info here!
Last edited by noeffred; 06-20-2010 at 08:49 AM. Click to view previous post history.
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I put the straight concentrate into a tray of water. As always, be very careful when working with the concentrate. It will mildly burn/numb your skin, and will do even worse if it gets into your eyes, mouth, etc.
Originally Posted by alexhill
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."
- Rob Tyner (1944 - 1991)
It's been my experience that vinegar added to the first wash will produce longer scale prints but it may also mordant the tray used for processing. I'm not very precise about how much I use but I would recommend 50 mll of 5% white vinegar per liter of water. If you are having massive bleed off add some tween to the mix prior to coating your paper.
Originally Posted by alexhill
Also I mix traditional cyanotype with 2 Parts A to 1 part B.
I never tire of recommending Hahnemuehle Fine Art Pearl. It clears better than any of the other H-muehle paper, and the finish is wonderful. And it had better be, at those prices....
Another very good paper is Bienfang 360. It's a thin paper so you need to dry mount the print to get the full paper brightness. Also a bit weak when wet and anything larger than 11x14 can be a PITA. It's cheap compared to other papers used for alt process - 50 sheets of 9x12 for $10 or so. It's also very good for Van Dykes.
Final wash was with a bit of hydrogen peroxide to brighten the blues.
Originally Posted by donbga
I have tried the vinegar in the 1st bath, but it mostly just made a mess of my trays.