An excerpt from Ruth Brown’s book Cyanotypes on Fabric where Ruth explains how to prepare the fabric for printing.
This is a very simple process which has been used for over 150 years but, to ensure that you and the environment are kept safe, please handle the chemicals carefully and read the health and safety advice in Appendix I before you begin. Use sensible precautions but don’t become so paranoid that you can’t enjoy a wonderful process.
Choosing your fabric
Cyanotypes work on a variety of surfaces but, being a textile artist, I use natural fibre fabrics, usually silk or cotton but also linen, hemp, rayon and silk/viscose velvet sometimes. The light-sensitive solution won’t penetrate any of the synthetic fibres I’ve tried; it looks fine when you put it on the fabric and when it’s been exposed but it disappears when it’s washed. One Internet site suggested spraying starch on synthetic fibres to anchor the cyanotype solution on to the fabric. Unfortunately the starch washed away during the processing, taking the cyanotype image with it. I haven’t by any means tried every fibre available so if you are in doubt, do a test piece and see what happens.
To remove the sericin from silk use the recipe from Yoshiko Wada’s book ‘Memory on Cloth’ – p194. Weigh the fabric you want to scour then take 10% of that weight in soda ash(washing soda) and dissolve in 40 times that weight in water (1ml = 1g). Simmer the silk in the solution for 30 minutes. Allow to cool then rinse VERY well, adding a splash of vinegar to the final rinse if you live in a hard water area. Alkaline conditions can damage your cyanotype badly so the final rinse wants to be in neutral/ slightly acidic water.
Example: 100g fabric needs 10g soda ash in 4000g water= 4 litres
Whatever you choose must be clean and free of any surface treatments, including fabric conditioners. You can buy from a supplier who specifies that their fabrics are ‘prepared for dyeing’ (PFD), which means they should be free of any surface treatments that could stop the cyanotype solution adhering to the fibres.
Clothing such as t-shirts may well have a surface dressing on them and should be washed before use.
If you do wash fabric or clothing use one of the products recommended in the chapter on ‘Taking care of your Cyanotypes’ so that you don’t accidentally leave any residue in your fabric that might damage your print. Powdered detergents particularly should be avoided as undissolved particles may ‘spot’ your print.
One further point on this, some silks still contain the natural gum sericin, that the silk worms use to stick the cocoon together. This will reduce the amount of cyanotype solution being absorbed into the silk. The sericin can be removed by scouring with soda ash (see the side panel) but it’s much easier to buy suitable fabric in the first place.
If you have a particular project in mind then it’s worth giving a bit of thought to the surface of the fabric you’re going to use. Different surfaces will give different results – a rough or loose weave will break up the detail of the images whereas a fine, smooth weave will allow a very sharp, detailed image. Here are some examples of a simple photogram on different fabrics.
The velvet is particularly intriguing as the light often doesn’t penetrate through the pile to the backing so the image is on the pile only!
The main advantage of preparing the fabric yourself is that you have the choice of fibre and weave from a delicate, dreamy silk chiffon, or a crisp, cool linen through a smooth, tightly woven cotton to a rich, sumptuous velvet. You aren’t limited to what is commercially prepared, you can pick the most suitable fabric for your project. The only natural fibre fabric that I’ve had trouble with is wool. I can only assume that the lanoline in the wool stops the solution penetrating.
What do you need to get started?
Most of the items you need for this process are cheap and easily found.
- A set of scales with 1 gram divisions is quite adequate for this process so some kitchen scales will do, postal scales can be found at stationery suppliers or, alternatively, you can go to a laboratory /photographic supplies company who will certainly have something suitable.
- A plastic or pyrex measuring jug for mixing the solutions
- Plastic or wooden spoons for getting dry chemicals out of their containers and for stirring to dissolve them.
- Storage bottles plus labels and a waterproof pen.
- The relevant chemicals – see the next section.
- Your choice of clean, dry natural fibre fabric.
- Dust mask, gloves, protective clothing
- A small funnel can be useful for transferring the dissolved chemicals into storage bottles.
- A large, soft brush such as a hake or household paint brush, or a small sponge.
- Frame and pins (optional)
- Plastic clothes line and pegs (optional)
It’s worth stressing that all the utensils you use for this process should be marked and should not be used afterwards for food preparation.
Firstly you need to prepare your light-sensitive solution.
The two chemicals used are:
- Ferric ammonium citrate (sometimes called ammonium ferric citrate), which is a green powder. It absorbs moisture from the air so keep it in an air tight container. It is also a very light powder so it’s best not to have a window open while you are measuring this out as it can fly everywhere.
- Potassium ferricyanide, which is in the form of bright red crystals. Read the section in the Health and Safety Guide on this chemical – it is classed as an irritant so you need to take suitable precautions but it is nothing like as nasty as the name might suggest. There is another chemical with a VERY similar name, potassium ferr(o)cyanide rather than potassium ferr(i)cyanide – not the same thing.
There is also a brown version of ferric ammonium citrate and a comparison of the properties of both types is given in Mike Ware’s book (see bibliography).
The two properties that are perhaps of most interest to us are that the green version gives a slightly higher speed of printing and gives a brighter blue than the brown version.
If you want to know more about this area of the subject consult Mike Ware’s book (see bibliography)
as it gives thorough and interesting descriptions of the history, the recipes used and the chemistry of the cyanotype process.
There are many different recipes given for the light-sensitive solution in various books and on the Internet. They nearly all use similar proportions of the two chemicals ie roughly twice as much ferric ammonium citrate as potassium ferricyanide by weight. Although the proportions of the chemicals are pretty constant the dilutions given vary widely. As most recipes are quoted for use on paper I started out using Barbara Hewitt’s recipe for fabric and have found that it gives beautiful results and a good colour on fabric and paper so I’ve used that one ever since.
Preparing the solution
- Shut the windows while you are handling the dry chemicals
- Put out the cat and the kids and take the phone off the hook
- Put on gloves, a dust mask and something to protect your
clothes in case of spills.
- Work on a surface that can be wiped down when you are finished or put old newspapers down first.
- Get out the equipment and the chemicals you need
Weigh out the chemicals:
Work out roughly how much solution you are going to need for the fabric you are going to treat. The amount of solution you need will vary depending on the weight and fibre of your fabric.
Not surprisingly heavier fabrics absorb more solution than light ones. To give you a rough idea to start with you can use the amounts given below. These figures are based on fabric 114cm/45 inches wide. Since these are only guidelines I haven’t differentiated between a metre and a yard in length.
|Fabric||Approximate quantity of solution|
|Silk/viscose velvet – short pile||375ml / 13fl oz per metre/yard|
|Prima cotton – medium weight||140ml / 5fl oz per metre/yard|
|Silk habotai 10||70ml / 2.5fl oz per metre/yard|
|Silk Chiffon 3.5||35ml / 1.5fl oz per metre/yard|
|If you are weighing out small quantities of chemicals, it can be handy to use paper cake cases (muffin cases). These can then be discarded with the other protective papers when you clear up.|
The basic cyanotype recipe is as follows:
15g / 1/2 oz potassium ferricyanide plus 30g / 1oz ferric ammonium citrate to 250ml / 8fl oz warm water. Use either metric or imperial measurements.
Weigh out the appropriate amount of each chemical, with a dust mask and gloves in place. Then replace the lids on the containers and put them away.
Mix the solution
Measure out the amount of water you want to use then stir the crystals/powder slowly into the water bit by bit in a plastic or pyrex jug.
All solutions should be stored in well-labelled glass or plastic bottles or other non-metallic containers. I found an old coolbox worked very well for storing bottles of light-sensitive solution and treated fabrics as it was light-proof and was easy to carry round. HOWEVER, I don’t have children visiting my studio who could confuse a coolbox with bottles of liquid inside for something to drink – use your common sense and label everything carefully.
After you’ve mixed your solution clear up your working space and wipe down the surfaces with a damp cloth – there are almost always particles of the chemicals that have ‘escaped’. It’s safe to remove your dust mask at this point but keep your gloves on until you’ve treated and dried your fabric to avoid getting the solution on your hands. This way you avoid, as with all dyes and chemicals, potentially developing a sensitivity to the solution. Prevention is definitely better than cure!
All the alternative photography books that I’ve read, say to mix each chemical in water separately and store them separately. The two solutions are then combined in equal quantities when you are ready to use them. I’ve tried storing the solutions separately and in the combined form. The ferric ammonium citrate seems to grow slimy mould fairly quickly on its own but I’ve never had that problem when it’s mixed with the potassium ferricyanide. I have no idea why.
Since potassium ferricyanide is light-sensitive on its own and the purpose of the ferric ammonium citrate is to speed up the process and darken the end colour, I thought I would try producing a print with potassium ferricyanide alone.
After a very lengthy exposure of 2 hours on a hot sunny July day, I ended up with a delicate white image on a pale turquoise background.
A frequent question is what form of cyanotype chemical/solution/treated fabric keeps best. My own experience is that:
- The powdered form of the chemicals will keep pretty much indefinitely IF they are kept cool and dark.
- I’ve used the solution after 3 months with normal, good results BUT it was stored in a cool, dark place.
- Treated fabric is much more difficult to store successfully EVEN if it’s kept cool and dark. I usually wrap treated fabric in light proof fabric (the sort that you use to make blackout blinds) and store it in a cool place but it still has quite a short shelf life. After only a week it can start changing colour. You may still be able to use it but it may give you a pale blue image on a prussian blue background rather than the usual high contrast one.
Don’t forget that the solution you’ve prepared is light-sensitive, so coating and drying your fabric needs to be carried out in artificial light or indirect natural light. In my house it’s the sort of place where my cat wouldn’t lie; she likes warm, sunny places whereas cyanotype solution likes more shaded spots on the other side of the room. If the solution or your treated fabric starts turning blue then UV light is getting to it from somewhere!
Pour out enough of the solution for the amount of fabric you want to treat into a plastic or pyrex jug.
Using a frame
Since I don’t usually prepare large quantities of fabric at a time I pin my chosen material on to a wooden silk painting/batik frame. My frames are made from four pieces of 2″ x 1″ wood glued and screwed at each corner but you could use an old picture frame just as well. Tear a piece of your fabric slightly bigger than the frame and pin it to the edges so it is supported and air can get to both sides to help with the drying process. Tearing rather than cutting keeps the grain of the fabric straight.
If you are using a frame to support your fabric, stand the frame on its end. Give the solution a stir just before you use it and, using a hake or other large, soft brush (or sponge), dip it in the solution, wipe the excess liquid off on the edge of the container, so it doesn’t dribble, then paint the solution on to the fabric starting at the top and working down. Take your time and aim for an even coating. Don’t get it so wet that it drips – this is just a waste of solution and can make an awful mess! Remember that the solution will ‘travel’ through the fabric after you paint it on so you don’t need to paint right up to the edges. Also, try and avoid getting the solution on any metal pins you might have used as the solution may react with the metal and give you nasty, dark marks.
The advantages of using a frame are that the fabric is kept under light tension, it allows air to move all round the fabric, helping the drying process and it gives you something to hold other than damp fabric if you need to move the fabric about while it’s wet.If you are treating velvet, it’s easier to paint the solution on with the fabric upside down ie on to the back of the fabric. The solution then wicks down the pile without distorting it.
A variation on the frame method given above is to lay your fabric on to a smooth piece of plastic or glass. Tape the corners so that it doesn’t move around too much, then paint the solution on.
Wash your brush or sponge thoroughly in water as soon as you’ve finished applying the solution and wipe up any splashes or spills, otherwise inconspicuous droplets of yellow liquid will turn into dark blue stains. If you do get blue stains on floors or surfaces then normal household cream cleanser will usually remove them.
You then need to leave the fabric to dry in a dark place. How dark is dark? Well, if it’s a warm day and the fabric dries quickly, a shaded corner is enough. If you are going to have to leave it for any length of time it will need somewhere genuinely dark. I use the bottom of a little-used airing cupboard, which has the added benefit of being warm as well as dark. You could use an old wardrobe with well-fitting doors. You can also use a hairdryer or fan heater on a low setting to dry the fabric but keep the airflow moving so it dries evenly or you may get unattractive tidemarks.
If you want to prepare larger quantities of fabric in one go you can immerse the fabric into a bowl or tray of solution, let it soak in for a few minutes, then squeeze out the excess solution. Make sure the solution has been thoroughly and evenly absorbed, especially with large pieces of fabric. The solution can be concentrated in the
folds of the fabric so move it around with gloved hands to get even coverage.
Barbara Hewitt suggests putting the wet fabric through a wringer to remove excess solution. She folds in one direction, passes it through the wringer and then folds in another direction before wringing again.At the end she passes a damp towel or rag through the rollers to clean off any residual solution that might contaminate later pieces.
The treated fabric can then be dried in a domestic tumble dryer at the lowest setting. I found it took about 20 minutes for a couple of metres of medium weight cotton or heavy silk and as little as 10 minutes for very light weight silk. If you want a smooth background to your print then take the fabric out of the tumble dryer as soon as it’s dry, otherwise the creases can give a really interesting texture to your background. Don’t forget to wipe your dryer out thoroughly at the end to avoid getting blue stains on your next batch of washing. Also, if you have a glass door on your tumble dryer make sure it isn’t in direct sunlight…
Treated fabric can also be hung on a plastic clothes line to dry, again in a dark place. If you can arrange for suitable ‘blackout’ blinds in your bathroom you could fix a clothes line or airer over the bath with a couple of inches of water or damp papers in the bottom to catch any drips.
The instructions so far have largely assumed that you want a smooth even background for your print, but textures and patterns can become an interesting element of your design. Here are some suggestions you can try.
- Apply the solution with rough brush strokes so that you can see the brushmarks when the fabric is exposed. This works better on heavier fabrics; the solution tends to flow along thinner ones, especially silk, in the same way that dyes do, but in this case you sometimes get nice crinkly edges to the dried solution.
- If you are drying your treated fabric in a tumble dryer, don’t be in a rush to take it out when it’s dry. The creases formed when it cools down will show up in the background of your cyanotype. I really like the textures formed in this way.
- You can also use kitchen roll, cotton wool or a sponge to dab the solution on with or you can drip or rag roll it on. All will give you different effects, some of which will please you more than others.
- Until the fabric has been exposed, moisture getting on to the treated fabric will leave a mark. This means that if you lightly spray your fabric with water either before you’ve placed your design elements or after, you will get a mottled effect on your background.
- If you put the fabric on a rough surface while you apply the solution and leave it to dry there, you will get a pattern on the background that reflects the roughness of the surface, rather like the effect of a brass rubbing.
If you are lucky enough to get a warm, sunny day when you have time to do some cyanotypes you don’t need to dry the fabric completely before using it: you can expose it while it’s damp. This appeals to me as I’m not very patient but I just don’t get enough hot, sunny days in the north of England to have much experience of this method. I can, however, say that you can get some very strange effects, including halos, using a sunbed with damp fabric which you may or may not like. NB water and electricity together are not a good idea so make sure any damp fabric doesn’t come into contact with anything electrical.
Although this book is primarily about cyanotypes on fabric I couldn’t resist incorporating some examples on paper including this lively image by Mary Monckton.
Mary used a soft brush to swipe the solution on to Bockingford paper in random strokes. She picked the poppy flower and columbine leaf and then made a layered sandwich of hardboard, foam, paper with plants, and glass all held together tightly with bulldog clips and propped to catch the sun. As she works in New Zealand it took only a few minutes in summer to change from the green to grey colour indicating that the exposure was done. The paper was then thoroughly rinsed, dried and finally, pressed under boards overnight.
What a lovely result!
Using a resist
You can restrict the area of the fabric you are going to print very precisely by using silk painting techniques.
Those of you who have done traditional silk painting will be familiar with using gutta/outliner (strictly speaking gutta is solvent based and outliner is water based but I’m going to use outliner here as a generic term).
An outliner restricts the flow of paint or dye on the fabric by forming a waterproof line. You can then paint within the line without the dye/paint spreading outside the shape. So, if you draw the shape you want to print with your outliner the cyanotype solution will stay within the shape you’ve drawn. This works best on thinner fabrics; on thicker ones the outliner doesn’t always penetrate to the back so you may need to repeat the outliner on the back of the fabric, going over the design a second time.
To test if there are any gaps in your outliner, before you apply the cyanotype solution, paint clean water inside your outlined shape. Wet fabric is temporarily darker than dry fabric so you can see any leaks where there’s a gap. If you do have a gap, dry the fabric thoroughly, apply more outliner to the gaps, let it dry, iron it to set and test again. Dry everything well before you apply the cyanotype solution. I used this method to produce the Cloud Bird above.
A resist is something that stops the flow or penetration of a dye or paint on a fabric. The outliner described above is one but you can experiment with others. For instance in their book Photo Art, Tony Worobiec and Ray Spence describe a process called Photobatik which utilises the fact that oil and water don’t mix.
One version they describe uses Vaseline to stamp an impression of a face onto paper. Cyanotype solution is then applied over the top. Since the solution is water based it doesn’t adhere to the areas coated in vaseline and they remain white. After processing, the paper is washed in water with a little mild detergent to remove the vaseline. This could obviously be used on fabric and could be extended by using other design elements over the non-vaselined areas to create further patterns or textures.
If you are interested in using other resists the thing to consider is whether the method of removing the resist will damage the cyanotype. Don’t forget that they are very susceptible to anything alkaline.
Storing your treated fabric
Once your treated fabric is dry then you can remove it from the frame, if you’ve used one, and carry on to produce cyanotypes straight away or you can store the treated fabric in the cool and dark for future use.
A good solution is to use the light proof bags that photographic paper comes in, as they are designed specifically for this purpose. However, now that digital photography is so popular these bags have become scarce. Bin liners, although they are black, do usually let light through. Hold one up to the light and you’ll see what I mean. Alternatively, wrap the dry fabric in a plastic bag and then in aluminium foil or a foil bag. You could also wrap the treated fabric in light proof fabric which is what I usually use. However you keep the light away, the fabric needs to be cool, dry and dark.
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