Cyanotype toning: the basics

 

“No one but a vandal would print a landscape in red, or in cyanotype.” (Peter Henry Emerson: Naturalistic Photography for Students of the Art, London: Sampson Low, Marston, Searle and Rivington, 1889) Citation courtesy of Luminous Lint/Mike Ware

I happen to agree with Mr. Emerson so I tone pretty much all of my cyanotypes.  I have several posts about different toners and how they (generally) look, but this post will go over the basic process of toning and try to troubleshoot a few common problems. 

Toning a cyanotype involves two basic steps: a bleach phase, and a toning phase.  Every toner I know of contains some type of tannin in it: tannin chemically binds to the iron in the emulsion and changes the color.  If I understand this process correctly, it produces a form of gallic acid – used in dyes and inks, especially medieval ones.  I’ve read that gallic acid is normally corrosive, but I’ve never found this to be the case with toned cyanotypes.

If you’re concerned about the archival quality of your toned cyanotypes, Dr. Mike Ware (inventor of the “New” cyanotype process) has said that his family photo albums contain what he’s pretty certain are toned cyanotypes – because they look very similar to other alternative processes it’s easy to confuse with Van Dyke prints or Kallitype prints.  I’ve personally never had issues with mine – I’ll get back to you in some 20 years or so and see if that’s still the case. 

Keep in mind that toners are funny things – you can mix and match things, you can vary the sequence of bleach and toner and get different results.  I have a lot of good results with simply leaving the prints in the toner for long periods of time without bleaching at all.  Take things one at a time – don’t try to tone or bleach multiple prints together.  Experiment and have fun with it!  Just remember that the key to a successful toned print is to wash well between steps. 

1. Toning Preparations:

Before you start your toning, always:

  • Age your prints at least 24 hours for the emulsion to harden.
  • Pre-wet your prints in filtered water to allow the solutions to penetrate the paper fibers evenly.
  • It’s a good idea to have multiple prints – toning is fickle, you never know what you’re going to get.
  • Plan to leave the print face down for long periods of toning, or plan enough time to “babysit” the print – agitate it while face up in the toner.

2. The Bleach Phase:

Bleaching is a tricky thing.  The purpose of bleaching is to help break down the iron a little so that the tannin in the toner can “grab on” easily.  If your water is heavily chlorinated, you may not even need to bleach your prints.

How much you bleach really depends on how you coat, how much emulsion is on the paper, and what toner you’re using.  If you bleach too far, you lose shadow density.  If you bleach too little, your shadows will stay a stubborn blue shade while your highlights cooperate.

Bleach types: the most common form of bleach solution is Sodium Carbonate.  That’s Washing Soda, usually found in your grocery store’s cleaner aisle, or at a photography chemical supply store.   Don’t confuse this with Sodium Bicarbonate – baking soda – it won’t react the same way. 

Other types of bleach that I’ve used are Ammonia and regular chlorine bleach.  Ammonia stinks, horribly, and usually produces a browner image.  Chlorinated bleach destroys paper fibers and is better left to your laundry. 

My typical bleach solution is about 1-2 teaspoons of Sodium Carbonate combined with 1 Liter of water.  If your print turns a bright purple the second you place it in the solution, it’s too strong.   Play with the solution until you’re comfortable with the rate of bleaching.  As you practice bleaching, you’ll notice that it’s a good idea to yank the print out a few seconds before you think it’s ready – the print will continue to bleach a bit while starting to rinse. 

Always rinse the print well in running water between the bleach phase and the toning phase.

3. The Toning Phase:

All cyanotype toners are pretty much variations on a black/brown/purple theme.  Certain toners are more efficient and stain less, while other toners produce a wider range of possible colors.  Keep in mind that all toners will stain your paper base a little despite your best efforts.  (please note that the following links lead to blog post about the toners, or examples of the toner shade.)

Tea toner:  Most tea toners that I use are brewed for about 10 minutes in  25o mL of hot water, then added to a 1.5 Liter of room temperature filtered water.  I use about 8-10 small tea bags, not a very accurate measurement!  Every type of tea has a different quality or color to it – make sure that you use teas with tannin in them like black tea or green tea – white tea, red tea, and most herbal teas don’t have enough tannin to do anything to your print. 

Green tea produces an eggplant/black shadow, and is so mild that it doesn’t stain the paper base too badly.  If you’re toning a high key image, green tea will sometimes produce a really cool pink highlight.  It has a tendency to split tone for me because of my double coat of emulsion. 

Black tea will stain your paper the most, but it produces a lovely warm black/brown shade that’s nearly impossible to get anywhere else.  I generally use a Lipton tea product for iced tea, but any black tea will work.  If you want an easy split toner with warm highlights and blue shadows, black tea is the fastest way to get it.  

Earl Grey tea: avoid this one – it has a lot of oils in it that can damage your print.

Tea toners work really well with a minimum of bleaching, but they do require a longer immersion for the iron to shift.  I normally tone prints in tea for about 2 hours, but depending on the print, it’s taken up to 8 hours.  Some people suggest that tea toners should be hot for a faster toner – in my experience that shaves about 30 minutes off the toning time, and stains the paper much worse.   It’s a good idea to let the print sit in clean filtered water for about 10 minutes before the final rinse to help remove some of the excess tannin.  All tea toners should be used freshly brewed – they lose potency after a day and should not be reused.

Tannic Acid Toner:  This stuff is a royal pain to work with.  It can produce the closest thing to a true black, but it’s far more likely to screw up, or produce a weird purply brown shade.  It has the widest range of color tones that I’ve seen in a toner, but you have absolutely no control over what you get.  Be extremely careful how much bleaching you do, because this toner is totally unforgiving if you go the slightest bit too far.  

Done well, this toner produces the least paper staining – however, I’ve run into some chemical issues that I don’t quite understand that leave my paper the shade of cardboard.  (I’ve narrowed it down to interactions with the tap water, or the age of the toner.)

Tannic Acid is produced from wood chips, and is extremely hard to mix into a solution.  It’s a gummy mess.  Because of this it’s difficult to estimate how much I use, but generally about a Tablespoon mixed into a Liter of water is a good place to start (and then remove the gummy bits.)  A good tannic acid solution should be almost clear, and will take a minute of sitting in filtered water to fully tone out.  Toning times for tannic acid are usually quite short.

If mixed with distilled water, tannic acid toner will last for a few weeks/months.  A little mold is normal, just filter the solution every time you use it.  Once the solution starts turning a dark brown or granulating (tiny little granules appear – not sure what they are) it’s time to start fresh.  Tannic acid is also quite expensive, and only available at a photography chemical supply store like Photographer’s Formulary. 

Coffea Toner: I love coffee toner.  It’s a cold toner, as opposed to the warmer tea shades, and it leaves the paper pretty close to the original color.  It will still stain, just not as badly as tea.  Coffee doesn’t produce a true black, but more of a blue/black like a blackbird’s feathers.  The highlights will stay pretty clean so make sure your contrast is good and your highlights aren’t blown out. 

I generally use the cheapest instant coffee I can find – about 4-5 heaping tablespoons of instant coffee dissolved into 250 mL of hot water, then added to 1.5 Liters filtered room temperature water.  I’ve read that other people have great success re-brewing used coffee grounds – since I don’t drink coffee I can’t exactly test this. 

Coffee toner doesn’t seem to take quite as long as tea toner, but expect at least an hour of toning, perhaps more.  Again, it’s a good idea to let the print rest in a water bath before the final rinse.

Wine Tannin: This is my new favorite toner, and I don’t have that much experience with it yet.  So far, it produces a nice dark shadow and a brown/tan highlight on a fairly regular basis.  It can be rather fickle if you keep the solution for a long period of time, so I suggest storing this toner no more than a month. 

Wine tannin is basically the same thing as tannic acid, but produced from a different source.  It’s designed to use in microbrewing so it mixes into solution a lot easier.  It leaves the paper almost paper white, producing almost no staining.  It’s slightly cheaper than tannic acid, but since it requires more to produce the same effect – half an ounce of wine tannin mixed into 1 L of water – the price is probably pretty close.  I use the powdered version, but some stores have a liquid solution available. 

Wine tannin has a tendency to put any coating discrepancies on display.  Unless I use the Christopher James variation listed in the link (toss the print into the tannin instead of bleaching first) I lose some of my highlight detail.  Like the tannic acid, it works pretty quickly.  Wine tannin also has a weird chemical reaction that can turn my paper to a cardboard brown, requiring a water bath before the final rinse. 

Troubleshooting:

1. My print looks faded!  What happened?  You probably bleached the print too far.  Try test strips in varying times to get a better idea of what works – the ideal is to tone your shadows dark without losing highlight details.  Usually this means bleaching until the shadows are a dark purple and the highlights are slightly yellow.

2. I left the print in the toner forever, but it’s still blue!  What now?  Rinse the print for at least 5 minutes and go back to the bleach bath.  After bleaching again – just a little, rinse it again for 5 minutes and put it back in the toner.  Your initial bleach probably didn’t break the iron down enough.

3. The print toned nicely, but now that it’s dry I hate it!  Why does it look so flat?  I don’t know why, but that’s normal for a toned cyanotype.  Try brushing a diluted solution of acrylic gloss medium onto the print to bring back the shadow depth and give the surface a little shine.  It will look like it did when the print was wet.

4. Why can’t I produce the same results each time?  What am I doing wrong?  Nothing.  That’s a quirk of toning.  If you have a batch of prints that need to look similar, try toning them all at the same time with the same solution.  Otherwise you run the risk of variations that you may or may not like.  If you’re still having issues, stick with the basic tea toner – it’s a little less fickle.

5. My print looks mottled – it didn’t tone evenly.  What’s going on?  If you’re leaving the print in the toner for a long period of time, make sure you place it face down.  Paper floats oddly, and you may end up with “dry” spots that don’t tone evenly.  If you’re toning face up, make sure you agitate the print constantly.

6. My print has a bright blue round spot on it!  Yup, the curse of the air bubble strikes again.  Make sure the print is lying face down – ease the print into the toner slowly and work all the air bubbles out past the far edge.  If you already have the blue spot on it, try a quick rinse, bleach bath, and return the print to the toner for a bit to remove the blue.

7. My shadows are blah.  What happened to my perfect exposure?  Your original shadows need to be a nice, deep, cobalt blue to tone dark.  If your shade of cyanotype isn’t dark enough, it’s not going to tone well.  Read this tutorial and do some experimenting with your paper and your developer first before you try toning again.

Cyanotype: basic process tutorial

Technically this should be a handy little video.  Since that involves a video camera and me actually talking (horrors!) I settled for some illustrating pics instead.  I’ve been meaning to do a little tutorial of my process for a while and finally got the camera out yesterday while printing.

I’ll go through the entire process from coating to drying, with some troubleshooting tips at the very bottom.  Again, I’m not an expert.  This is how I do things – they work for me, but your variables may differ.  A large part of the fun of working with alternative processes is what happens when you experiment.

1. Coating the paper

I don’t have pics of this, mainly because it was dark while I was doing it.   I double coat my paper with a Japanese hake (brush.)  The key to this process is to do it swiftly, carefully, and don’t glop emulsion.  It’s a good idea to tint some water a light green color with watercolor and practice your strokes.  Coat under a low light situation: I use a strand of small garden lights – Christopher James says a strand of Christmas tree lights.

My coating method is: strokes across the entire sheet, then down the entire sheet.  This evenly distributes the emulsion.  It’s a good idea to shake off excess emulsion or drag the brush over the edge of your container to keep from putting too much emulsion on: it doesn’t take much.  After the paper goes matte (a minute or so) repeat the process for the second coat.  Be very careful not to grind the brush into the first coat.

Let the paper dry flat for at least 1 hour, preferably 2 in a dark room.  No lights.  After the paper is bone dry (don’t touch the emulsion!) put it in a light safe bag overnight.  The emulsion needs to age for a little bit, but not over a day or so.  Drying with a blow dryer and subsequently printing should be avoided.

2. Exposing the image

I always test the print time with a simple test strip before I start printing.  I know the basic print time for my images – my digital process is streamlined enough that (if prepared correctly) all my prints should need the exact same print time if the conditions are the same.  It’s best to print in full sun, but any sort of UV exposure will work.  Cloudy weather is a little more unpredictable and will take a minimum of double your sunny exposure time.

Always load your negative under low light – once the paper is sensitive you risk fogging the paper: lightly exposing the paper so that you lose contrast and highlights.

The negative needs to be held flat and still on the paper.  An expensive hinged contact printing frame is nice, but not necessary for cyanotype.  My printing frames are simple glass held together with bulldog clips – make sure you don’t use UV resistant glass.

I try to angle my printing frames to match the sun so that the exposure is even.  I’ve heard this increases the contrast, but since my digital negative adjust for that I have no idea how much this affects my prints.

A properly exposed print will reverse:   the highlights and midtones will turn a green/blue, while the shadows look slightly solarized.  A single coated paper will turn the light brown that you see on the edges of this print, while a double coat will go a darker green.  It should look overexposed, because part of the emulsion washes off.

3. Developing the print

I use a 1:10 ratio of vinegar to water for my developer because of the pH of my tap water.  A little vinegar is good, too much will turn the paper into a slightly graded paper and affect your contrast.  No vinegar will produce a slightly lighter blue.

Drop the print into the developer face up and agitate.  Don’t let the water sit still: emulsion will pool and stain your highlights.  Keep agitating until the print has turned completely blue: your highlights may still stain a little yellow, that’s ok.  Drop the print face first in a filtered water bath for at least 5 minutes to finish the development process and allow the water to fully penetrate the paper fibers.

If you look carefully at this image, you’ll see that it’s slightly overexposed and a light shade of blue.  All cyanotypes need to oxidize before they reach their true color – after the water bath, you can accelerate this process by dropping the print into a weak (a capful per liter of water) bath of hydrogen peroxide.  The overexposure will be slightly bleached by my nasty chlorinated tap water in the final rinse – I slightly over-expose to compensate for this.

4. Final Rinse

I final rinse all my prints for at least 10 minutes in running water (face down.)  This clears out the last of the chemicals left over by the development process.  Be careful when picking up the prints: a wet cyanotype will smear emulsion if you touch it.  Once the print dries and hardens, rewetting will not result in more smears.  I usually let my prints rest on blotting paper for a few minutes to soak up the majority of the water, then drip dry on a line until fully dry.

If you plan to tone your prints, let them age/harden for at least 24 hours before you tone.

5. Troubleshooting issues

  • My entire print washed off in the developer, what did I do wrong?   You didn’t expose long enough for the image to fix.  Try a few test strips with stepped increments to find the best printing time.  Don’t be surprised if your printing time is long for a really dense negative.
  •  My image has far too much contrast: You need to adjust your negative.  For ortho film, use filters when printing (it’s been a while, I think you make a super low contrast negative.)  For film negs, try vinegar.  Lots of vinegar.  For digital negatives, read this blog post.
  • My coated paper is dark green/blue/anything but light green when I go to print: dark green usually means contaminated chemicals.  Blue means it got wet – high humidity will do this, or bagging before the print is fully dry. Best case, recoat and try again.  Worst case, you need to remix your chemicals and be super careful to avoid contamination.
  • Why does my print look washed out? Different papers will produce different color tones of blue.  Try Canson Montval if you want my shade of blue – avoid cheap art papers because they will have more chemicals in them that interact with your emulsion.  Also try double coating for deeper shadows.  As in all photography, if your negative isn’t perfect, your print won’t be either.  Make sure your contrast on the negative is perfect. 
  • My image is blurry! Is your negative completely squashed against the paper?  Did it move during printing?  Are you using the negative correctly? (i.e. facing the paper on the correct side – for digital, ink-to-emulsion works best.)  Remember, cyanotype is part of the paper and the paper “tooth” becomes part of the image.  If the paper is particularly rough, try sizing it before you coat with emulsion for a clearer image. 
  • My print stained.  What went wrong? Proper washing is key.  Sometimes your rinse water will react to the emulsion – if this is the case, let it sit in a filtered water bath for a while longer.  Make sure you never reuse your developer – always prepare fresh water/vinegar for each print or risk a blue stain.  
  • Ack! My negative is dusty/shows fingerprints!  I usually wear light cotton gloves when working with my digital negatives.  If I notice a problem, usually the gloves will clean the negative without damaging it.  Dust/fur/brush bristles in the emulsion are far more a problem for me – duplicate prints are a good idea, especially if you plan to tone.  
  • My cyanotype print faded after a few months.  Cyanotypes like a slightly acidic environment, and sun will fade the print.  Shove the print into a book for a few days and let it sit: it should come back to its normal color.
  • I hate the flatness of my prints.  Is there anything I can do to make them shiny? Yes!  Try brushing a half-and-half diluted solution of acrylic gloss medium on a finished print.  This works really well with toned images, bringing out the shadow depth.  If you’re using a single coat of emulsion, try adding a tiny bit of gloss to the emulsion before you coat.  Mix well, or you’ll get streaks – you may have uneven toning issues with this method as well.
  • I don’t have a lot of sun in my area.  Can I use a facial tanning device to expose my prints? Yes, you can, but it’s not a good idea.  UV exposure units need to be built specifically for alternative processes or you risk exposure to yourself, uneven prints, and limited printing size.  You can build your own unit if you’re an electrician, otherwise, check out photo supply stores like Photographer’s Formulary or Freestyle Photographic Supplies and be prepared to pay a lot.  Like, $600 minimum. 
  • Why can’t I just buy precoated paper/prepared emulsion?  You can.  It’s just not ideal or cost effective.  Cyanotype is so cheap and safe (within chemical safety guidelines) that it’s better to mix your own and coat your own if you plan to make a habit of it.  Pre-mixed cyanotype emulsion uses the traditional formula – generally a slightly altered formula works better.  Mine (from college, thanks prof!) is listed here.
  • Um…my B solution is growing mold.  Is this a problem?  Nope, just filter it before you mix the emulsion.  Always make sure you mix solutions A and B with distilled water to avoid chemical contamination, but mold is normal.  Not a problem.
  • Why can’t I just mix up  the entire solution instead of mucking around with solutions A and B? Because it’s light sensitive and it starts to degrade about a day after you mix it.  Best to keep them separate – they last for years.  Just remember to lightly swish the solutions before you start pouring – some chemicals settle to the bottom.