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.