A paper for cyanotype must absorb the solution without falling apart in the rinse. Watercolour paper meets this need; a fairly thick, porous, non-glossy recycled paper can also work after a test on an offcut. Avoid ordinary printer paper. Choose a sheet of at least 200 grams, ideally 250 to 300, neutral or slightly acidic, then choose its surface according to the image: smooth for a detailed negative, more textured for a photogram.
Paper is the first choice that decides a print, before the salts and before the sun, because it is what holds the solution, withstands the rinse and gives the blue its depth or its dullness. In workshops, a good half of disappointing cyanotypes come not from a chemistry mistake but from an unsuitable support, too light, too smooth or treated in a way that hinders the reaction.
This choice rests on the sheet’s resistance to water, its absorbency and its surface. Once the support has been chosen, it still has to be coated, dried and stored after sensitising: these steps are also described here. Textiles and other materials are covered elsewhere. If you are new to the process, the cyanotype guide sets out the basics.
What paper weight for a cyanotype
Paper weight is the weight of the paper per square metre, expressed in grams, and it roughly tells you how thick and strong the sheet is. It is the criterion that separates a paper that will survive the rinse from a paper that will end up in shreds at the bottom of the tray.
Cyanotype goes through a water bath that soaks the support right through, sometimes for several minutes, and ordinary printer paper, at around 80 grams, cockles, becomes waterlogged and tears at the slightest rub. You need a paper that can take this immersion without falling apart, and that is the whole point of watercolour paper for cyanotype, designed from the outset to be soaked.
In practice, aim for a paper of at least 200 grams, with the comfortable range lying between 250 and 300 grams. An even higher weight, up to 600 grams, holds up perfectly but costs more and dries more slowly, with no decisive advantage in the result. To start with, a 300-gram watercolour paper offers the most sensible compromise between strength, price and ease of drying.
The fibre plays a part too. A cellulose paper is enough to learn with, while a pure cotton paper gives a more even surface and ages better. A watercolour-quality paper, neutral or slightly acidic, suits the process and preserves the blue over time.
Choosing a smooth or textured surface to suit the image
The same blue does not look the same depending on the surface of the sheet. The surface of watercolour paper comes in three main families, and each one steers the result.
- Hot-pressed, or smooth, paper offers a closed, even surface that renders fine details sharply, which makes it valuable for a print from a photographic negative where every nuance counts.
- Cold-pressed, the intermediate surface, remains versatile and forgives small irregularities in the coating.
- Rough paper, strongly textured, gives a more vibrant, textured blue, superb for plant photograms but less faithful on a detailed negative.
There is no right surface in absolute terms, only a surface that suits your image. For a portrait or a precise photo, go for smooth or cold-pressed, whereas for a print of a fern or of lace a more pronounced texture adds character. A common mistake in workshops is to judge a paper on its whiteness alone, when it is the surface that decides the final result.
Three watercolour paper surfaces, from smooth to more textured, seen in raking light.
How sensitising interacts with the paper
Once the paper has been chosen, it still has to be made sensitive by laying the mixture of the two iron salts on it. The quantities and the technique belong to the cyanotype recipe, which details the proportions and the two ways of applying the solution, by brush or by bath, and the step-by-step guide to preparing your cyanotype paper takes you through these steps from start to finish.
What matters here is how this technique meets the support. If you would rather not look for a paper yourself to begin with, the Sténoflex cyanotype kit provides ten sheets of watercolour paper already suited to the process, a handy point of comparison for getting started before you go on to test other papers.
A smooth, closed paper holds the solution on the surface and does not take kindly to too much of it, whereas a pronounced texture soaks it up deeply and needs a slightly more generous layer. On a very absorbent fibre, brush coating must stay brisk, with no going back over, because the layer becomes saturated and uneven. The visible brushstroke at the edge is in fact part of the aesthetic of the process, and many people deliberately keep it.
Whatever the method, work in the ambient light of a room, away from direct sun. An ordinary bulb emits too little ultraviolet to expose the paper, so you have time to spread the solution calmly before it dries.
Drying the coated paper
Drying is the step most often rushed, which is a pity because it determines how even the exposure will be. Paper that is not properly dry gives stains, tide marks and an uneven blue.
Sensitised paper dries away from light, in a dark or dimly lit room, laid perfectly flat on a rack to stop the solution running down the sheet and forming a darker band there. At room temperature, allow anything from thirty minutes to a few hours depending on the paper weight and the humidity of the air, and a hairdryer on a cold setting speeds things up without any risk to the coating.
The paper must be perfectly dry to the touch before you lay the negative or object on it and expose it, because paper that is still damp sticks to the negative, gives imprecise contact and a blurred or mottled image. This patience at the drying stage is one of the habits that separate a sharp print from an approximate one, even before you get to the exposure time in the sun.
Storing sensitised paper
You can perfectly well prepare paper in advance, which saves time on sunny days. Paper that has been sensitised and then thoroughly dried keeps for several weeks, sometimes a few months, provided you keep three enemies at bay: light, humidity and heat.
So store it flat in an opaque sleeve or a black envelope, somewhere dry and temperate, away from any source of ultraviolet. Stored like this it remains usable for a long time, even though its sensitivity declines slowly and old paper sometimes needs a slightly longer exposure.
One sign is unmistakable: if the layer spontaneously turns blue-grey while in storage, it has been exposed to light or moisture and is partly exposed.
Beyond paper
Paper is the ideal ground for learning, but cyanotype is not limited to paper. Cotton and linen are sensitised in the same way and stand up to washing, while other materials also take the process, from wood to primed glass.
The principles covered here, resistance to water, a suitable surface and drying away from light, remain valid from one support to another.
Frequently asked questions
Why does a heavily sized paper give a pale cyanotype?
Because overly strong surface sizing stops the solution from penetrating the fibres: the blue stays on the surface and comes away in the rinse. Conversely, a paper with too little sizing soaks up the solution and gives an uneven blue.
Do optical brighteners in paper interfere with cyanotype?
They are not ideal, and a paper without optical brighteners is generally recommended. The pH matters more, though: an alkaline paper, known as buffered, makes the blue fade in the wash.
Can you make a cyanotype on recycled paper?
Yes, if it is thick enough (at least 200 g/m²), porous and non-glossy. Some recycled papers are alkaline and can lighten the blue in the wash: do a test on an offcut before printing.
Éric Marais — Photographer, author of two books on pinhole photography (published by Pearson) and creator of the Sténoflex. He has run introductory workshops in alternative photography, from pinhole to cyanotype, from the very beginning.