How to get a better blue in cyanotypes

[Fulvio]

Ok, three days ago I began making cyanotypes. At the fifth attempt, after switching a couple of papers, I think I made an acceptable print. I had a problem with some watercolor paper: I believe it was a buffered paper and that caused a self-bleaching while it dried. Now I turned to a Fabriano cotton based paper. I had the print rest for one day after drying, it oxidized regularly and now appears just fine. As long as I understood, the ideal paper for cyanotype should be rich of fibers and low alkali. Is this right? If not, how I do select a paper for cyanotype? However, my real question is the following. The print I'm obtaining is, indeed, cyan-prussian blue in color. The hightlights are white and aren't stained. But compared to some cyanotypes I found in some books I believe I should try to get more richer and deeper blu. How I do accomplish that? Tomorrow I'll try to double-coat some papers to check if that's the way. Any other suggestions? thank you

 

[Mateo]

Are you double coating? I was never able to make a decent print with a single coat. Another thing is that they seem to get deeper color over the space of a couple of days. If that still isn't working try a little hydrogen peroxide in your wash water (10ml per liter should work, I just pour a little in). And that brings up another thing; if you are washing with tap water that is too alkaline it will have a bad effect on your prints. I don't use tap, just a final bath in distilled water.

 

[psvensson]

Are you using the traditional formula with an acid first bath? If you are, try adding half a teaspoon of potassium ferricyanide per 1.5 l water to the first bath, along with the acid. Watch your maximum density go through the roof. Saturation improves too.

A print treated that way doesn't darken further due to oxidation, but it's much deeper and contrastier (because of higher d-max) than a fully oxidized print with a straight acid or water first bath.

 

[Fulvio]

I use traditional cyanotype formula (as described in the book "Alternative Photographic Processes" by C. James)

Until this morning I just used single coated papers. Today I'm trying with double coating (the 1st coating layer is drying now).

I develop/wash my prints in water, not acid. I put the prints in a tray and change the water 3-4 times during a total of 5-12 minutes of bathing. Also, I add some citric acid (that is some drops of lemon) in my first bath, as suggested in some books.

While the new sensitized papers are drying, this morning I tried to bleach with sodium carbonate (1 tsp) an old print which was too dark... It worked!!

As soon as I can I'll try with hydrogen peroxide, thanks for suggestions. I'll post some more after new results.

 

[Mateo]

The peroxide isn't going to do anything that the citric acid from you lemon isn't doing already. Either one will work; the idea is to get the wash water PH to nuetral or slightly below as the cyanotypes are sensitive to an alkaline environment.

 

[psvensson]

The peroxide isn't going to do anything that the citric acid from you lemon isn't doing already. Either one will work; the idea is to get the wash water PH to nuetral or slightly below as the cyanotypes are sensitive to an alkaline environment.

This is not correct - the acid and peroxide do different things. The peroxide doesn't acidify the water, it oxidizes Prussian white to Prussian blue. A print developed in an acid first bath loses a lot less density in the wash, especially from the highlights. This means a much longer tonal scale.

I'm not sure lemon juice is going to do enough to make a difference, though. I use a tablespoon of citric acid powder to 1.5 l water as the first bath, in addition to the potassium ferricyanide. This makes a huge difference to the tonality of the print.

In his monograph on the cyanotype, Mike Ware recommends 1% solutions of nitric or hydrochloric acid over citric acid, but I don't want to mess with concentrated acid.

 

[Mateo]

You got a ph meter or some of the strips handy?

 

[psvensson]

You got a ph meter or some of the strips handy?

OK, OK, peroxide can act as an acid, but I believe it's too weak for this application. pH of peroxide solutions:

http://www.h2o2.com/intro/faq.html#15

It looks like straight drugstore peroxide solution has pH close to 6.

 

[Fulvio]

Thank you everybody for your suggestions.

So far, now I'm double coating my papers. I'm still using the Fabriano cotton paper. Finally I can get good blues. I tried to add potassium ferricyanide in the first bath, but I couldn't tell the difference.

On the other hand, with double coated papers the highlights are always stained... The stain color is light blue. On some prints I've successfully removed it with a bleach bath in sodium carbonate. I tried to apply it selectively with a brush and this method works too. But on some prints I have a light blue - veery light green staining. On the back of the papers I have some of this staining too! What it could be? I thought it could be some sensitizer that penetrated too deeply into the paper. Although, I expose the papers when they are bone dry. How I can get rid of this staining?

As soon I can I'll post some pictures.
thank you

ps - in the meanwhile, I tried to tone a print with coffee... It works!! Strong coffee, diluted with tap water, about 4-6 hrs in bath. The results with my coffee (just two small cups) is a split tone with black/deep brown tones and little deep blue in the shadows.

 

[psvensson]

I tried to add potassium ferricyanide in the first bath, but I couldn't tell the difference.

Bummer. Obviously there's more to learn about this. Thanks for trying.

Regarding your clearing problems, have you tried adding some oxalic acid to the sensitizer? I've heard this can help clearing.

 

[Fulvio]

Bummer. Obviously there's more to learn about this. Thanks for trying.

it is possible that I haven't seen any difference because of the poor quality of my negatives and the lack of a calibration. I haven't an inkjet printer and for now I'm trying with some (horrible) laser printer negatives. Thanks to a friend of mine, the other day I made some cheap ink jet negatives and still it is far better. I have no friends with Epson Ultrachrome printers, but I'm considering to buy one, perhaps one of their latest models. Another problem of my prints might come from the contact frame. I've built one myself, but it is not a good one; the contact pressure maybe is too light and images aren't sharp as in the negative. Do you know where to find large contact printing frames at a fair price?

Regarding your clearing problems, have you tried adding some oxalic acid to the sensitizer? I've heard this can help clearing.

Unfortunately I haven't oxalic acid and in my city it is difficult to find raw chemicals, I have to order them by mail. However, I do not really want to mess with toxic acids for now.

I haven't sized my sheets before coating. Maybe is this the cause of the excessive staining?

One last question: how much sensitizer do you use for each layer of coating? How much drying time do you let pass from the first hand of sensitizer and the second? Finally, how much time do you keep drying the finished sheet of paper before exposure? Do you expose your print facing directly sunrays or slightly behind in diffused sunlight?

thank you

ps - ever tried coffe or tea as toners with cyanotypes? the coffee did a nice work, but how about the archival status of the print?

 

[titrisol]

Oxalic acid is very safe, may burn your skin/eyes if you make contact with pure acid.
From JTBAKER MSDS:
Oral rat LD50: 375 mg/kg; irritation skin rabbit: 500 mg/24H mild; eye rabbit 250 ug/24H severe; investigated as a reproductive effector.

--------\Cancer Lists\------------------------------------------------------
---NTP Carcinogen---
Ingredient Known Anticipated IARC Category
------------------------------------ ----- ----------- -------------
Oxalic Acid (144-62-7) No No None

Unfortunately I haven't oxalic acid and in my city it is difficult to find raw chemicals, I have to order them by mail. However, I do not really want to mess with toxic acids for now.

I haven't sized my sheets before coating. Maybe is this the cause of the excessive staining?

One last question: how much sensitizer do you use for each layer of coating? How much drying time do you let pass from the first hand of sensitizer and the second? Finally, how much time do you keep drying the finished sheet of paper before exposure? Do you expose your print facing directly sunrays or slightly behind in diffused sunlight?

thank you

ps - ever tried coffe or tea as toners with cyanotypes? the coffee did a nice work, but how about the archival status of the print?

 

[psvensson]

Yeah, oxalic acid isn't that bad. You could also try adding a small amount of citric acid to the sensitizer just before coating.

 

[donbga]

This is not correct - the acid and peroxide do different things. The peroxide doesn't acidify the water, it oxidizes Prussian white to Prussian blue. A print developed in an acid first bath loses a lot less density in the wash, especially from the highlights. This means a much longer tonal scale.

I'm not sure lemon juice is going to do enough to make a difference, though. I use a tablespoon of citric acid powder to 1.5 l water as the first bath, in addition to the potassium ferricyanide. This makes a huge difference to the tonality of the print.

In his monograph on the cyanotype, Mike Ware recommends 1% solutions of nitric or hydrochloric acid over citric acid, but I don't want to mess with concentrated acid.

A couple of glugs of white vinegar will do just as well. Some users report using lemon juice and it should work when using a sufficient quantity in the clearing bath. Concentrated lemon juice should have enough citric acid in it to work ok.

I would avoid the potassium ferricyanide but I'm curious to see the differences you report. Can you post some examples?

Don Bryant

 

[donbga]

Thank you everybody for your suggestions.

How I can get rid of this staining?

Don't double coat. One of the keys to making nice cyanotype prints is the type of paper you use. Try Arches Platine with the traditional cyabotype formula with 2 parts A and 1 part B. The tonality, highlights, and DMAX will be outstanding. Use Vinegar or citric acid to clear the print. If your blues are washing away you are under exposing and or over washing.

Have you tried printing a series of step wedges to determine the minimum printing time with your light source, paper, and processing work flow? Doing so will help clarify what is going on with your cyanotype printing.

Don Bryant

 

[Fulvio]

as promised, here's some few scans

1) Dead Link Removed
double coated, negative from ordinary canon ink-jet print; the highlights aren't too stained (I had to apply a very little bath of sodium carbonate with a small brush, though); the blue tones are almost good to my taste, yet they could be improved (on the books I have the sensitized area outside the negative often it is extremely dark; on my prints they aren't). There's also a coffee-toned version of this negative (about 8-10 small cups of strong coffee, diluted in 1.5-2 liters of tap water, for 8 hours) Dead Link Removed

2) Dead Link Removed
this is one of my very first attempts - single coated, laser printer negative; the paper was an unknown watercolor paper... Even with 30-40 minutes of exposure, once dried the prints always "autobleached". I guess it was the paper (buffered?). After understanding this, I switched to a Fabriano cotton paper which didn't give this unfortunate result. But now I want to try something else. I'm not ready for top-quality dedicated paper. Which commercial paper do you suggest? Consider that I live in Italy; some papers avaiable in US maybe aren't avaiable here and viceversa.

3) Dead Link Removed
this isn't very bad; single coated, fabriano paper, samsung laser printer negative (very ugly); developed in water with lemon juice. The only problem, as I mentioned in the beginning of this thread, were the blue tones: too light. Maybe you can't judge by this digital image, but I assure you that it appears too flat. It was developed in water with concentrated lemon juice.

4) Dead Link Removed
this isn't bad too, but the highlights are stained. See those gray areas in the middle? It is the same problem with picture no. 5 (except tha this is overexposed and no.5 is underexposed). - Duble coated, fabriano paper, canon ink jet negative. I always do my exposures in direct sunlight, with the sunrays hitting the glass. This print was probably overexposed (20 minutes - I have made a contact frame that can be opened to watch the printing status, but I admit that I still can't tell when a cyanotype is ready or not). I guess I might get rid of the excessive blue with some sodium carbonate (this will cause the blue tones to lighten, though).

5) Dead Link Removed
this is very odd... I have at least three prints ruined like this. And also n. 4 and n.1 have a similar characteristic, although not so invasive. This print, however, was developed in winegar (I believe in 1:4 dilution). The print is underexposed, but I can't understand why - I made another print before this and I used the same exposure time, since I liked the first. Could it be the winegar? However, it didn't clear the print. Even after the bath I still could see some areas unclear, especially on the back. I could see the sensitizer on the back even when the paper was still unexposed. Before exposure it was yellow-greenish color; after exposure and during developing it was still greenish; I couldn't get rid of it during wash bath; when dried it turned light blue/gray. This could be the result of a double coating with too abundant (4ml per layer is abundant??) sensitizer and 1st coating layer combined with 2 drops of wetting agent. I might try with sizing all my papers, but I never sized a paper and must learn more about it. - Note: please don't consider the gray areas around the cyanotype "circle" - I didn't flatten the paper with the press, so the paper is all curled and what you see are just real-world shadows which the scanner captured.

If you need more informations about the making of these prints to comment on the tecnique, please tell me. I always used a standard cyanotype formula, diluted 1:1. I wash/develop my prints in trays, changing the water several times.

 

[Fulvio]

Don't double coat. One of the keys to making nice cyanotype prints is the type of paper you use. Try Arches Platine with the traditional cyabotype formula with 2 parts A and 1 part B. The tonality, highlights, and DMAX will be outstanding. Use Vinegar or citric acid to clear the print. If your blues are washing away you are under exposing and or over washing.

Have you tried printing a series of step wedges to determine the minimum printing time with your light source, paper, and processing work flow? Doing so will help clarify what is going on with your cyanotype printing.

I'll try with the oxalate, as soon as I can get some of it.

Another apug member (Mateo, page 1 of this thread) suggested to always double coat paper. Why are you suggesting single coating? With double coating I noticed darker blue tones. Although they are not as dark as I would. Is it the paper so important? Do you size the paper before coating it?

As for the stepping wedges, I will surely calibrate my negatives once I'll start producing them with my own printer - which I don't have (yet). I'll probably buy an Epson, like almost everyone else into alt. photography...

 

[Dug]

Check out the formulas and discussion at:

http://www.bostick-sullivan.com/c_cyano.htm

I have been doing Cyanotypes lately with Arches Aquarelle (sp?) - I tried the more expensive and the cheaper 100% cotton hot pressed papers and have had the most success with the Arches paper. I eliminated some of the variation I experienced from uneven coating by "floating" the paper in the mixture for an even coat (the chemicals are cheap, so I used 200 ml in the tray). Another thing you might want to try is getting your hands on a 4"X5" contrasty negative that you know the relative densities. If you can consistantly coat and expose a negative of known density, it will give you a leg up to start looking at the exposure variables.

At this point you may have too many different variables to get a handle on where you need to work to get consistancy. If you would like - PM me with your address (Italy?) and I can send you a test negative with known density and you can start narrowing down your variables.

 

[Mateo]

I'll try with the oxalate, as soon as I can get some of it.

Another apug member (Mateo, page 1 of this thread) suggested to always double coat paper. Why are you suggesting single coating? With double coating I noticed darker blue tones. Although they are not as dark as I would. Is it the paper so important? Do you size the paper before coating it?

As for the stepping wedges, I will surely calibrate my negatives once I'll start producing them with my own printer - which I don't have (yet). I'll probably buy an Epson, like almost everyone else into alt. photography...

I think you are going to find as many opinions as there are people printing in cyanotype. Dug from Seattle says he's getting good results with Arches watercolor paper and I've never gotten anything decent from any of the Arches papers with the exception of Platine. So there are some variables in the process that just can't be dealt with for all people the same. It probably comes down to a hunt a peck method of finding what works for you.

 

[psvensson]

Fulvio, I want to see your scans, but I'm getting "connection refused."

 

[psvensson]

Fulvio, I want to see your scans, but I'm getting "connection refused."

 

[psvensson]

I would avoid the potassium ferricyanide but I'm curious to see the differences you report. Can you post some examples?

Don Bryant

Sorry, scanner has died of old age! Will get a new one some day...