Category Archives: Photographic Processes

An introduction to the Chemigram process

The chemigram process is an artistic technique that involves the use of photographic materials and chemicals, but counter-intuitively will not generally be classified as a photographic process. Considering a fairly broad interpretation, photographic processes involve the formation of images by exposing some kind of sensitive emulsion to light. This may involve use of a camera, or may be entirely camera-less, but it is still “writing with light” as the formation of the image is dependant on the amount of light reaching each discrete point on the paper. As chemigrams are commonly (but not required to be) created in conditions of normal daylight, the photo-sensitive emulsion will be fully saturated by light almost immediately. It follows that the image formation is not based primarily on exposure to light, and thus precludes its classification as a photographic process.

Chemigram 1.8 olive oil resist, by Carol Shergold, licensed CC BY

Chemigram 1.8 olive oil resist, by Carol Shergold, licensed CC BY

The basic idea of a chemigram is that photographic paper is alternately & repeatedly exposed to both developer and fixer. Areas of the paper exposed to developer first will tend towards black (since the paper is fully saturated with light), and areas of the paper exposed to fixer first will tend towards white. Obviously if a plain sheet of paper is placed in a bath of developer the whole sheet will go black which won’t be too interesting. So the technique involves some method of influencing which areas of the paper get exposed to the chemicals at each step, thus forming the desired image. As such the process is best described as “writing with chemistry”.

The chemigram process was invented and pioneered by Pierre Cordier, who sub-divides the practice into three categories:

  1. Chemigram without resist. The developer / fixer will be applied directly to the paper, using paint brushes, sponges, etched plate, stencils, stamps or any number of other instruments. This technique takes the chemigram close to traditional painting practices. Pigment based paints have simply been substituted for photographic developer & fixer.
  2. Chemigram with resist applied by hand. The paper will be coated with some kind of product that resists the effects of the developer and fixer. As the paper is passed back & forth between the developer and fixer, the mask will gradually come off allowing the chemicals to form an image.
  3. Chemigram with resist applied by photographic process. Again the paper will be coated with some kind of resist, but in this technique the resist will be applied using some photographic process such as silk screen printing with photo emulsion. This takes the chemigram close to traditional photographic practices.
Prayer to the sun

Prayer to the sun by Balazs Sprenc, licensed CC BY-NC-ND

The variables

As with any artistic process though, there are no strict barriers – elements of each of the three categories can be applied in the same image if desired. For example an initial part of the image can be formed by painting developer/fixer onto the paper using a brush. Once that is completed, a resist can be applied to the remainder of the paper and further developed/fixed. The chemigram technique could also be combined with regular photographic processes such as photograms / lumen printing at the artists discretion. There are an immense range of factors that can be varied to influence the resulting image. A non-exhaustive list would include

  • Type of paper – resin, or fibre based, which manufacturer, which variety, fixed grade, or multigrade, etc. Any photographic darkroom paper ever produced is a candidate for use with the technique.
  • Age of paper – if you have a box of expired paper from 1960, don’t overlook it. Since the chemigram is commonly created in broad daylight, fogged paper is not a problem to worry about.
  • Type of resist – any product which will adhere to the paper even for a mere second, whether it be varnish, paint, masking fluid, honey, flour paste, egg, clay, butter, or wilder ideas
  • Additions to the resist – no need to stick with the basic product – if honey is too thin, add flour or sugar to thicken it up. If the resist is too transparent to see, add some dye / food colouring. The resist sticks too well, mix it with something that’s more soluble.
  • Application of resist – the resist applied with fingers, knife, brush, spray, stencil, roller, sponge, quill, etc. The tool used will affect the surface texture of the resist, which in fact can affect how evenly the chemicals penetrate the resist. For example, brush strokes left in the resist may transfer to the paper if the resist is porous to the developer/fixer.
  • Resist drying time – the length of time a resist is left to dry will affect how easily it comes off in the chemicals. Leave it the minimal time to adhere to the paper, or until it is 100% dry and hardened, or anywhere in between. The harder the resist has set the slower the chemicals will penetrate it, giving more time to work the image.
  • Ambient lighting conditions – while normal daylight is most common, a darkroom could allow for localized light exposure and/or combination with other photographic techniques. For example the paper may be initially contact printed, and then a resist applied over part of the image, letting the uncovered image fix immediately.
  • Area of paper with resist – the resist does not have to be applied evenly to the entire paper. Specific areas can be covered by resists, or left uncovered.
  • Damage to the resist – once coated the resist can be intentionally compromised to allow the chemicals to penetrate more easily. For example a knife can be used to cut through dried varnish. Or paper can be bent to crack the surface of hardened resists
  • Chemical types – different brands or mixtures of developers and fixers have different effects on the tones exhibited by the paper. If regular dev is not doing what you like, you can even try lith developers.
  • Chemical strength – more concentrated developer/fixer will speed up the process which may save time. Conversely less concentrated solution allow greater time to finesse the image
  • Toners / dyes – as with any photographic print, toner / dyes can be applied to adjust the colour of the final print
  • Time in the baths – the time spent in developer / fixer before switching to the alternate bath will determine how much time it has to penetrate the resist and bring out the tones of the paper. To get tones in between black and white, leave the print in the chemicals for less time, so the fixer/developer has not fully taken effect.
  • Application of chemicals – the developer / fixer can be applied by dunking the prints in trays, or it can be applied directly to the paper using a tool, such as brush, sponge, etc. The latter would allow for much more localized control of the image formation.

Any analogue artistic process will result in unique works, but with some processes it is practical to create editions of work that are fairly close to identical. This is particularly true of techniques that involve an element of printing whether photographic or not. This is not the case with chemigrams, especially when resists are used. There is a very strong element of non-deterministic behaviour in the creation of chemigrams with the result that even if the exact same steps are followed each time, each final image is likely to be considerably different. There is little scope for creating an edition of identical prints in the strictest sense – at best you will get a family of related works, each with their own distinct character and qualities.

Draco, by Nate Lawson, licensed CC BY-NC-ND

Draco, by Nate Lawson, licensed CC BY-NC-ND

The equipment

Getting started with the chemigram process is remarkably straightforward, with little equipment and no darkroom required. The minimal setup would consist of 3 darkroom print trays, a 1 litre measuring jug, a bottle each of black & white developer and fixer and a packet of black & white photographic paper. The print trays, jug and B&W paper are easily found on ebay, as many people are selling off old darkroom equipment for next to nothing – 15 pounds for all those items would be easily attainable. There’s no need to worry whether the paper is outdated, or fogged, as chemigrams are usually created in daylight. The developer and fixer can be obtained online from a couple of suppliers in the UK for no more than 10 pounds each for 1 litre bottles.

The process

To start off mix up 1 litre of developer at the recommended dilution (typically 1:9) and pour it into one tray. Do likewise for the fixer and pour it in the second tray. Put a litre of tap water in the third tray. The temperature of the solutions in each tray should be approximately 20C but accuracy is not important for this process – changes in temperature will merely affect the speed of the process. One could use stop instead of water for the third tray, but again that isn’t too important – both the developer and fixer will get so badly contaminated with the residue from the resists that they’ll be disposed of before cross-contamination becomes a significant issue.

Assuming you intend to only ever use the paper for chemigrams, you can take sheets straight out of the lightproof black bag in daylight. If you ever want to use the pack of paper for real darkroom work though, make sure you have a changing bag or some other means of removing sheets of paper in the dark, to avoid fogging the remainder of the pack.

Take a sheet of paper and apply whatever product you wish to use as resist. A good place to start is with something that is soft, spreadable and sticky – thick honey, syrup or mustard. Coat the paper completely, or just partially, as you wish. Then place the paper into either the developer or fixer tray, again it doesn’t matter which. Let the paper soak for an arbitrary amount of time. If desired, physically rub away at the resist a little, or just let the chemicals slowly dissolve it. Then take the paper out of the tray and put it in the plain water tray to wash off chemicals. Once washed, put the paper into the other chemical, and again rub the resist if desired. Repeat this, switching between the developer and fixer each time. Either continue until all the resist has gone away, or stop sooner and just wash the remaining resist off the paper. When all resist has gone, put the paper into the fixer for a final time. With the final fix done, wash the print in a fresh bath of water for as long as is needed for the type of paper being used to remove all trace of chemicals.

The story of nine dots

The story of nine dots, by Balazs Sprenc, licensed CC BY-NC-ND

The rest

A mentioned earlier, the process was pioneered by Pierre Cordier and he is still probably the most well known practitioner. There was a rare exhibition including some of his work at the Victoria & Albert museum in 2010/2011, for which there is an associated video worth watching online. For a range of articles looking at contemporary artists using the chemigram technique, the extensive nonfigurativephoto blog is worth reading.

The images in this posting are creative commons licensed chemigram works from a couple of flickr users. In the next blog posting I’ll present some of my own initial experiments with the chemigram technique.


Ultraviolet: World Record Cyanotype

At the start of May, the Wellcome Collection organized a festival, On Light, exploring the relationship to light, which naturally included a number of events related to photography and photographic processes. I went along on Saturday 2nd for “Ultraviolet: World Record Cyanotype”, where Melanie King, Constanza Isaza and Andrés Pantoja were aiming to create the world’s largest ever cyanotype print covering approx 110 square meters (actual dimensions 7.5m x 15m). I took along my ZeroImage 2000 camera to document the event, first shooting a roll of Kodak Tri-X 400 black and white 120 roll film and then a roll of Fuji Superia 400 colour 120 roll film.

The cyanotype was to be created on fabric, consisting of a number of individual sheets sewn together beforehand to achieve the world record size. The sensitization of the fabric with cyanotype chemicals was performed the evening/night before in St John on Bethnal Green Church. This of course had to be done at night to avoid premature exposure, considering also the long time needed to dry the fabric properly before it could be packed into a black light proof bag for transport. Prior to working with the full sized fabric, a couple of small pieces (estimate about 1.5m x 1m) were used for testing exposure times. Two willing volunteers lay down on the test strips for about 20 minutes, which were then quickly washed. As well as serving as the test exposure, they were interesting demonstrations for the assembled crowd to witness & understand what was going to be done with the full sized fabric.

The test sheet was put through a couple of cold water washes to develop the cyanotype image and wash away remaining chemicals

The test sheet was put through a couple of cold water washes to develop the cyanotype image and wash away remaining chemicals

The results of the 20 minute test exposure showing the outline of a volunteer who lay down to form the image

The results of the 20 minute test exposure showing the outline of a volunteer who lay down to form the image

With the successful test out of the way, the organizers moved forwards to assemble a large group of willing volunteers to be the subjects of the full size record attempt. The general idea was for the volunteers to simply lie down on the fabric in a self-determined pose. In addition to that, there was a collection of random objects, predominantly circular, which were to be laid out on the fabric to give some contrasting shapes in the image. The fabric was swiftly unrolled in a courtyard off Malet Place, the subject & objects took their places and so the exposure had begun.

The courtyard was certainly not comfortable, but the volunteers had to remain still for 20 minutes none the less. If you didn't know what was happening you might think there had been an outbreak of a deadly virus

The courtyard was certainly not comfortable, but the volunteers had to remain still for 20 minutes none the less. If you didn’t know what was happening you might think there had been an outbreak of a deadly virus

At the end of their nap time, the subjects had to pick themselves up and collect the other random objects that were placed on the cyanotype.  The places where they had been just showed a faint ghostly presence

At the end of their nap time, the subjects had to pick themselves up and collect the other random objects that were placed on the cyanotype. The places where they had been just showed a faint ghostly presence

Upon completion of the exposure, the fabric was quickly bundled up and transferred into the large water tubs for washing. This followed the same process as washing the test sheet, except that it took many more changes of the water to fully develop the classic cyanotype blue (& rinse off the chemicals) due to the immense size. After a lot of hard work by the organizers and their team of assistants though, the final result was ready to be revealed.

After washing the final developed cyanotype image was revealed to the world.

After washing the final developed cyanotype image was revealed to the world.

The ghostly impressions after exposure were transformed into dramatic figures after developing

The ghostly impressions after exposure were transformed into dramatic figures after developing

The sheer scale of the finished cyanotype was incredible to behold. The world record attempt was a dramatic success.

The sheer scale of the finished cyanotype was incredible to behold. The world record attempt was a dramatic success.

As can be seen from the images, the world record attempt was an unqualified success. The exposure was spot on, resulting in very dramatic high contrast outlines of the test subjects, even with the dull overcast day. The range of different poses the volunteers had chosen to hold were fascinating & entertaining at the same time. The only so called “problem” to come out of the day, was that of deciding what on earth to do with the finished cyanotype fabric. It would be a shame for it to remain in a bag for the rest of its life, but due to its size, there are obviously few locations / galleries which have the ability to display it. None the less it was recently announced that the fabric will be travelling to Spain to be displayed in the Revel-T festival this summer

The event was inspirational and left me with an enhanced passion for working with the cyanotype process. To anyone attempting to break this record though – don’t underestimate the amount of work involved in achieving something that on the surface sounds rather simple – nothing is easy at this scale, as the organizers and their assistants will attest.

The organizers and some of their assistants. From left to right, Hollie Quinn, Melanie Kathryn King, Francesca Polo, Constanza Isaza Martinez and Tres Peces Navegando.

The organizers and some of their assistants. From left to right, Hollie Quinn, Melanie Kathryn King, Francesca Polo, Constanza Isaza Martinez and Tres Peces Navegando.

Caffenol, aka developing B&W film w/ instant coffee

Peak Imaging is my film processing lab of choice, since they have provided consistently good results and have very fast turn around times. Even if I can send the film off and get it back within 3 days though, that is still 3 days longer than it takes me to see digital photographs. A number of friends develop their own B&W film at home, since you don’t actually need a proper dark room – a small changing bag suffices to transfer the films into the light proof processing tank. I’ve thought about doing this before, but the idea of dealing with lots of chemicals was never too appealing. While researching B&W film processing recently, I happened across an article on a website (I forget which exactly) mentioning that it is possible to develop film using home-brewed developer based on little more than instant coffee. The moment I read about this, I knew I had to try it out for myself.

The science bit

After a little more reading, I’ve learnt that Caffenol developers have 3 key ingredients, each serving a specific purpose.

  1. Instant coffee. This contains a variety of chemicals including caffeine, but the one that is thought relevant to film development is caffeic acid. This is a phenol which acts as the first developing agent reducing the silver halide to metallic silver, revealing an image on the film base.
  2. Washing soda. Photographic developing agents require an alkaline solution to activate them, but coffee is fairly acidic. Washing soda, aka sodium carbonate, acts as the accelerator raising the PH to a suitable level for the developing agent to operate.
  3. Vitamin-C. Caffeic acid on its own will result in very long development times, so the Caffenol-C recipes add ascorbic acid (aka vitamin-C) as a second developing agent to further speed up the reactions.

Reinhold’s basic recipe for these 3 ingredients, Caffenol-C-M, is only suitable for use with film rated at 100 ISO (or lower). It is said to cause fogging of high ISO films during development. I primarily shoot Tri-X 400 in my ZeroImage 2000 pinhole camera, so the slightly more advanced, Caffenol-C-H recipe, was the one to go for – the ‘H’ stands for “High Speed”. This adds a fourth ingredient, Potassium Bromide, which acts as a restrainer to prevent fogging. The minor irritation is that the latter isn’t a common household ingredient. Fortunately Reinhold has since found that Iodized salt can be used in place of Potassium Bromide, and this is fairly easily found in supermarkets.

Getting started

I hadn’t done any film processing at home before, so the first step was to obtain the minimal set of equipment. The Patterson film processing kit is a cost effective way to obtain the core pieces, vs buying them all separately, though searching for second hand items on eBay could probably cut cost even more. In addition, I got the cheapest digital scales that Silverprint stocked and a concertina storage bottle for storing fixer between use.

The recipes linked above need a little tweaking based on the precise ingredients used. In particular washing soda comes in a variety of formulations, anhydrous, monohydrate & decahydrate. Most of the recipes published on the web assume use of the andhyrous (waterfree) formulation, but it is possible to figure out the amount by which to adjust the quantities, by heating in an oven and measuring the weightloss. In the UK the most easily available washing soda is Dri-Pak Soda Crystals, for which people have already verified an adjustment value of x2.7.  There isn’t any available data on the amount of caffeic acid in the instant coffees you can get in supermarkets, but fortunately this doesn’t seem to matter much – people have got acceptable results with almost any instant coffee. So don’t waste money on the most expensive brands – pick any old cheap bottle of instant coffee. Pure Vitamin-C powder is available in most pharmacies in the UK, but at stupidly expensive prices. Holland & Barrett have tubs at slightly more reasonable prices, particularly when they have 2-for-1 special offers available. For the final ingredient, iodized salt, the only brand commonly available in UK is Cerebos Extra Fine Iodised Table Salt.

Caffenol-C-H ingredients

Caffenol-C-H ingredients

Caffenol-C-H-UK Recipe

With all that in mind, the following is a specific recipe derived from Reinhold’s Caffenol-C-H using ingredients available in the UK to make 1 litre of solution. I’m calling this Caffenol-C-H-UK.

  • 150g Dri-Pak Soda Crystals. Cost: £1.00 for 1kg
  • 16g Holland and Barrett Vitamin-C powder. Cost: £6.99 for 170g
  • 40g Sainsbury’s Rich Roast Instant Coffee. Cost: £2.00 for 200g
  • 12g Cerebos Iodized Table Salt. Cost: £0.75 for 400g
  • water to make 1000ml of solution. Cost: free(-ish)

For a single 35mm film only 300ml of solution is required, so the quantities are

  • 45g soda crystals. Cost: £0.045
  • 4.8g vitamin C. Cost: £0.20
  • 12g coffee. Cost: £0.12
  • 3.6g salt. Cost: £0.006
  • water to make 300ml of solution
  • Cost: £0.37 per roll.

while for a single 120mm (medium format) roll film, 600ml of solution is required

  • 90g soda crystals. Cost: £0.09
  • 9.6g vitamin C. Cost: £0.40
  • 24g coffee. Cost: £0.24
  • 7.2g salt. Cost: £0.01
  • water to make 600ml of solution
  • Cost: £0.74 per roll

Compared to mail order film processing at about £4-5 per roll of film, or high street processing of as much as £10, Caffenol is very cheap. If you can get cheaper sources of Vitamin-C powder, then the cost will be drop even further. Of course this assumes your time is free too.

Mixing the developer

The critical thing to bear in mind when mixing up caffenol developer is that you are not making soup, rather you are attempting to perform a specific set of chemical reactions. For this reason, it is not advisable to simply mix all the ingredients in one go, instead follow a precise order of mixing.

  • Fill the measuring cylinder with half the target volume of water from the cold tap. ie if the end goal is 600ml of solution, then fill with 300ml of water
  • Pour in the soda crystals and stir for a couple of minutes until they are well dissolved. Since Dri-Pak soda crystals are a decahydrate, the temperature of the water will typically drop 8-10 degrees and the volume of solution will increase. NB anhydrous soda crystals would have instead raised the temperature.
  • Pour in the vitamin C and stir, at the very least until it has stopped fizzing.
  • Pour in the instant coffee granules and stir for about a minute. The solution will now be a disgusting looking brown sludge :-)
  • Pour in the the Iodized salt and stir some more.
  • Top up with further tap water to achieve the final desired volume of solution. The developer is intended to work at 20 C, and mixing in the soda crystals will have lowered it to about 10 C. So when topping up to the final volume, add hot water at first until it is 20 C, then finish topping up with cold tap water.

After everything is thoroughly mixed, allow the developer to stand for 5 minutes to ensure all the desired chemical reactions have completed. If you could not get the temperature to exactly 20 C during the mixing phase, then sit the cylinder in a basin of hot or chilled water as necessary to adjust to 20 C, stirring all the time.

Caffenol mixture

Caffenol mixture

Processing the film

From this point onwards, fairly standard dark room film processing rules apply. Pour the Caffenol into the film tank, turn the stirrer several times and then seal the lid. Invert the tank 3 times and then bang it on the work surface to dislodge any bubbles. The quoted development time from Reinhold’s site is 15 minutes, but for the images produced with my pinhole camera on Tri-X I find 13 minutes gives a better result. I suggest going for 15 minutes at first, and if the result is too high contrast (indicating over development) try reducing it a couple of minutes next time around. During the development time, invert the tank 3 times at the start of each minute.

Caffenol does not require a chemical stop liquid, so when the development time is up, invert the film tank pouring the caffenol down the sink, then rinse multiple times with cold tap water. Keep rinsing until the water is no longer brown, as this minimizes subsequent staining of the fix. Once rinsed, add any regular fix and follow the normal process for that. Since my kitchen has no air extractor fan, I use Fotospeed odourless fix to minimize the fumes. Despite multiple rinses, the fixer will probably still end up stained light brown, but this does not appear to affect its ability to work in any way, so don’t discard it.

Once fixed, a thorough wash is needed. For this fill the tank with water, replace the lid and invert 5 times. Replace the water and then invert it 10 times. Replace the water once more and invert it 20 times. All that remains is to take 600ml of water, add a drop of Kodak PhotoFlo and dip the film squeegee into it. Then pour the water into the film tank, turn with the stirrer stick and invert it once to ensure the film is well coated. Now take the film off the reel, squeegee the water off it and hang it up to dry.

Film drying

Film drying

For some example images processing with Caffenol, browse images on my new portfolio website