Cyanotypes - super easy photo prints at home.

Picture of Cyanotypes - super easy photo prints at home.
The goal of this instructable is to explain the cyanotype process. Cyanotype is a super easy (and cheap) photo printing process that you can do at home with a few special materials. Digital pictures printed as cyanotypes make great gifts.

Some history, from wikipedia :

Cyanotype is an old monochrome photographic printing process which gives a cyan-blue print.

The English scientist and astronomer Sir John Herschel discovered this procedure in 1842. Though Herschel is perhaps the inventor of the cyanotype process, it was Anna Atkins, a British scientist, who brought the process into the realm of photography. She created a limited series of cyanotype books that documented ferns and other plant life. By using this process, Anna Atkins is regarded as the first woman photographer.

Process Overview
1. Mix two chemicals to create photo sensitive solution of 'sensitizer'.
2. Brush, smear, or soak the sensitizer into cotton-based watercolor paper.
3. Create a negative image on a transperency with a laser/inkjet printer or copy machine.
4. Place the negative over the dried, sensitized paper.
5. Expose to UV light.
6. Wash the image in water to develop.
7. Hang to dry, and enjoy!
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Step 1: Chemistry

Picture of Chemistry
Cyanotype requires a simple 2 part 'sensitizer' that is sprayed, brushed, or smeared onto a high-cotton content paper.

The cyanotype is perhaps the safest photo printing method. Still, basic safety measures should be observed. Cover your work surface, don't use any utensils that will be used for food, and wear safety gear. In the picture below I'm decked out in safety glasses, a DIY style face mask, and heavy rubber kitchen gloves.

The basic formula (from here):
100 ml water and 25g green ferric ammonium citrate is mixed together.
100 ml water and 10g potassium ferricyanide is mixed in a separate container.
The two solutions are then mixed in equal parts.

What I did:
I could not find the required chemicals in the Netherlands. My cheapest option was to buy from the Photographer's Formulary in the US (even with international shipping).
FAC 100 grams
PF 100 grams

Most tutorials suggests making 100ml of each solution. I didn't want to store these liquids so I made a much smaller batch. I chose to make 5ml of each solution, to be mixed for 10ml total sensitizer.

I do not have a scale, so I estimated the volume of each chemical I needed based on the overall size of the bottles (100g). I mixed a very rough 0.5g PF and 1.2g FAC each to 5ml de-mineralized water (used for clothing irons, car batteries, etc. Sold in bottles in the Netherlands for ~50 cents). These were mixed individually and then combined, as per the instructions above.

Step 2: Paper

Picture of Paper
A cyanotype can be printed on almost any paper, cloth, or even tile. I used 100% cotton water-color paper from an art paper store. It was not fancy (about 2 euro for a huge sheet), nor thick (~170 lbs?). Some people are more careful about paper selection. For other's views, check out the Alternative Photography forum here .

Brush, spray, or soak the sensitizer into the paper.

Leave the paper to dry, or speed it up with a hairdryer set to low.

Step 3: Negative

Picture of Negative
The cyanotype process is a negative photo process. Black on the negative becomes white in the final print.

I loaded my digital pictures into photoshop. Removed the color information (for a B&W image). Did image->invert for the negative.

The negative can be printed on an inkjet, laser printer, or copy machine. I printed my negative using an inkjet printer with inkjet transparency sheets. I used "high quality black and white" mode (which uses the color inks to make B&W). I did this because the colors are more UV-resistant than the black (in my experience, I make positives for doing UV/foto printed circuit boards that need very high accuracy).

The negative was placed with the ink against the paper. This is the same thing I do for PCBs - it really helps prevent unwanted light leakage.

The paper and negative were placed in a cheap picture frame to keep everything flat and aligned.

Step 4: Exposure

Picture of Exposure
The print is put under UV light until the exposed sensitizer turns from yellow-green to 'confederate grey'. The sun or a UV tanning lamp can be used as a UV source. See the The Big Cyanotype Exposure Survey for more information on exposure times and techniques.

What I did:
The frame with paper & negative was placed directly under a home tanning lap set face-down on a table. This is exactly the same setup I use to make PCBs, albeit with positives and photosensitive copper-clad fiberglass board.

I did a number of exposure tests. First I tried recommendations from the survey, 15 minutes and 10 minutes. These were way over exposed. Next I tried 5, 3, 2.5, 2, 1.28 (the exact time I use for PCBs), and 1 minute. I settled on 1 minute and 45 seconds.

Step 5: Developing

Picture of Developing
First, wash the print in demineralized (distilled) water until all the yellow areas of unexposed sensitizer are washed out of the paper.

Next, rinse it in the sink (under running water) for a few minutes.

This can be your final step - hang the image to dry.

If you are impatient (like me), dip the print into a solution of 125ml (.5 cups) water with one cap full hydrogen peroxide to finish the development instantly. Without this treatment, the image will change to its final color over a few hours (as it dries). Note: at first I made a new solution each time, but then I used the same solution for 10 or so prints without a decrease in potency. Rinse the print again to clean it of any remaining hydrogen peroxide. Hang to dry.

Step 6: Other stuff

Picture of Other stuff
I tried toning and bleaching on a few of the 'rejects'.

I simply steeped a bag of tea in hot water from the tap for a few minutes. I tossed the tea and print into a shallow container. It soaked for 5-10 minutes. The color is somewhat 'Diesel' denim or brown/black, depending on the observer.

I also did a bleach test. I mixed a heap of baking soda (naturium bicarbonate) in some warm tap water. This bleached the image clean off the paper in a matter of seconds. I know it works, but I have not tried to tune or control the process.

My UV source is too close to the paper. Rather than getting over developed spots, I get light-ish underdeveloped bars where the reflector doesn't adequately distribute the UV light. This will probably be fixed by raising the UV light a few inches over the paper (of course this will throw off my exposure times...)

I'm really really pleased with my results. My images were not washed off by the Amsterdam tap water (my initial concern). A total lack of precision chemistry didn't hamper my ability to get great prints.
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I'm guessing that it would be difficult to use this in a pinhole camera setup? or a DIY camera?

I'm mostly interested in this for making botanical prints.

xnr2 years ago
I found a Dutch supplier:
brsram3 years ago
Just tried the print (managed to get chemicals after a lot of trying!) Wonderful! I just used stuff like keys, leaves and got lovely prints.

Problem I am facing is in making sure the mix gets spread evenly all over the paper. Tried with 1/2" thick brush, reasonably good, would like better solution. Squeegee? Ink roller? Any ideas?


brsram3 years ago
How much of the sensitizer do you need to cover an A4 size paper? I cannot get readymade cyanotype paper in India, but should be able to get the chemicals. B R Sitaram, Ahmedabad, India
ian (author)  brsram3 years ago
No much, just a very light brushing.
brsram ian3 years ago
so, when you made your 5ml + 5ml of solution, was it adequate for 1 A4 sheet?
ian (author)  brsram3 years ago
I've heard this process works on wood as well? Do you think it'd be plausible to do a cyanotype on say a guitar then finish over it?
ian (author)  LeviMan_20014 years ago
Fantastic idea. I would guess, I did it to an (Instructables) shirt. You'd need to be able to wash it.
crazyg4 years ago
its not like radioactive dude :-)
cahun5 years ago
real nice :D i live in holland as well and i was wondering if by now youve found a dutch suplier for the chemicals, please let me know :D
fegundez15 years ago
If you are using caustic soda ,or actually almost any of the chemicals described here you can get large amounts cheap!! At the neighborhood pool supply store,thats swimming pools. I dont know why but it seems that many of my customers and about half of the U.S. seem to want to add many toxic products to their environment! Just check out the shelves at the store sometime.Great instructable though I have never tried any of this stuff but I shall give it a shot
bbarrup5 years ago
where did u get the chemicals for this from
Bostick and Sullivan is a pretty good supplier
jihgo8 years ago
An Australian supplier of these chemicals is:
neubaten jihgo6 years ago
hey man thanks for the tip, Im in NZ and from ajax finechem here it was gonna cost me $300 odd dollars for 500g of each chemical, but at vanbar its $118 (NZD), less than half the price! chur bro
lowercase6 years ago
... and by the way, I've found that the best way to "paint" the paper with the sensitizer is to use a foam brush it'll give you an even coating.
lowercase6 years ago
I used to add a BLEACH bath at then end of the process and then rinse it. Yeah, that's common bleach or sodium hypochlorite (NaClO) it will give you a REALLY DEEP BLUE TONE, don't ask me why but it happens, just prepare a weak solution. Try it, you'll be surprised!!! (My formula is little bit more complex than yours but I think it should work with yours too). please tell me if this works with your formula.
Biotele7 years ago
I am old enough to remember getting photocopies using this process at school. I don't have pleasant feelings when I see a cyanotype, unfortunately. (I just learned what they call this process from you).
My guess is that what you experienced in school were actually copies made using a ditto machine.
"Both the isopropanol and the methanol found in ditto solvents are toxic substances. These chemicals can cause a host of medical problems when humans are improperly exposed" Now I got an excuse for my bad performance at school.
i'd think that by now you wouldn't need one! who's still quizzing you about your school days?
These things are engraved in my mind. I still remember the classroom and If I concentrate enough I can remember what was the test about.
in my teens i spent weeks trying to make one of these machines work (it was abandoned in an office machine repair place where i worked at the time) after much doing i managed to get negative dark brown and wet copies out of it, but all the fun came to an end when whatever fluids were left in the machine were used up. good times....
hmm tea toning thats pretty good. we usually use dark coffee in our lab. its cheaper than the kodak toner. plus it helps yield a more mellow and evenly toned print. and we dont have the health risks of heavy metal selenium poisioning.
agreed, but the coffee tastes terrible after you tone a few prints...
etherealpr8 years ago
For those seeking less toxic options, many educational supply houses and hobby shops stock sunprint paper, which is similar if not identical to cyanotype. No scary super-toxic solutions to dispose of!

See for one example
They're NOT "super-toxic"! Oh, I give up. Let's go back to discussing improvised explosives, ninja weapons, and homemade weapons. Heaven forbid we should do anything involving CHEMICALS (*gasp*)
too true
is there a cheaper, yet still reliable solution for exposure than a 150$ light box? I know I can use sunlight, but doing that reliably would be difficult. For example, would it be feasible to put a tanning bed light in my bathroom temporarily?
The sun. Obviously. I've many prints using the sun. T-Shirts, fiber paper, etc. Just weigh it down with a piece of glass, and carry it out into bright sunlight. Forget the filters. Just experiment with exposures. You can also see the chemical change as it develops.
Also, if you do your history research, they didn't have electric UV lights in the 1800's. The sun is the original UV source. You can also make Van Dyke prints (brown, different process) with the sun.
I'm not sure what the spectral sensitivity of the cyanotype is but if it's anything like daguerreotypes (orthochromatic: sensitive only to blue and green light), then you could slap a red/yellow/amber filter over the image and then develop using the sun. Are cyanotypes sensitive to the full visible light specturm? You could also, I suppose, buy a UV-only "visible-light" filter to block out all light except UV. That would be pretty sweet but expensive. B+W makes one, I believe.
There seem to be a few options for a normal sized UV bulb (mostly reptile lights). I believe I'll buy one of those and do contact prints until I get up the gumption to try to build my own enlarger. Thanks for the help!
edit: see the image in my instructable or my avatar: I'm developing a daguerreotype using a halogen lamp and a piece of Amberlith.
I'm still partial to using an actual photo enlarger to print with. It takes some tweaking to determine your exposure time, but I've used it succesfully with standard cyano-blueprint paper (available from reprographics stores) There's also the option of just having a large scale b&w negative version of an image plotted onto a semi transparent material like mylar or vellum then using that directly in a blueprint machine to expose your images... A word of warning though... the developer in blueprint machines is ammonia and the first time you use a blueline machine... wooboy are your eyes going to water.
ian (author)  krylonultraflat8 years ago
I used a 5 euro face tanner from a second hand shop. Its worked great for PCBs for over a year now. I don't know if it gets cheaper than that (the sun I guess...).
ian (author) 8 years ago
I had a little extra stuff left so I tried to cyanotype my instructables t-shit. It worked pretty well.
RaNDoMLeiGH ian7 years ago
Does this wash out of fabric? If not, oh, how cool!
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