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  • Writer's pictureRitchard Allaway

29/04/2024 - Soil Chromatography

10th - 19th April

Experimentation: Making the Unseen, Seen




Now some of you might be wondering what soil chromatography is, therefore this conversation will discuss what this curious form of photographic practice is, how I came across it, why I am working with it and how it supports my research into making the invisible landscape visible.


Soil chromatography is a form of photographic practice that captures certain elements and qualities with soil samples. The photographic process was developed by the Russian botanist Mikhail Semyonovich Tsvet in 1900. Tsvet’s chromatography technique used adsorption methods to separate living materials such as plant pigments through extraction processes mixing alcohol solutions with calcium carbonate. It was later developed in the 1930’s by Steiner and Kolisko to assess food quality and in the 1950’s, Martin and Synge developed a new form of chromatography known as partition chromatography from a lab in Leeds. 


The experimental developments with soil chromatography made it become a low-cost and physical scientific method to qualitatively picturise the relationships between organic and non-organic chemistries within soil, compost, and plants. Although the idea of stating that soil chromatography was a form of photography would be difficult to argue for, but the visual evidence produced from soil chromatographic experiments would allow scientists and others to visually study a certain type of imagery. Latter experiments used silver nitrate powder and salt, and when combined become extremely light sensitive. This form of chemical compound is a key component within analogue photography. Using silver nitrate and salt would allow researchers to separate natural materials and extract minerals and organic forms on a different chemical scale. 


Soil chromatography is used across the world, and as stated it is a cheap and cost-effective method to work with and easy to analyse. The overall objective is to visually study the soil ‘picture’ produced through the chemical compound reaction and partition. The picture indicates the health and quality of soils which includes clear visual analyse of microbiology, minerals, and humus’.


My understanding and awareness about soil chromatography was limited but due to current developments within my research (in which I am writing a chapter on soil) I have been directed towards this form of photographic analysis. Through certain journals and texts, I have been able to begin exploring the processes involved in soil chromatography. It is my intention to utilise soil chromatography to study soil quality including the exoelectrogens found within soil collected from my walking residencies in specific landscapes of northern England and southern Scotland. I am hoping to demonstrate the existence of invisible living systems through the visual photographic development, which in turn could support my inquiry into why certain sensations and feelings occur when situated in a specific landscape. Will the visual evidence, analysed through a scientific technique demonstrate an invisible landscape aesthetic?

 

To create a soil chromatographic image, I had to gain access to several different materials. These included the following:


-       Soil sample

-       Sodium Carbonate (soda crystals)

-       Silver Nitrate Powder

-       Water

-       Qualitative Filter Paper (150mm)

-       Petri Dishes (small & large)

-       Dark Bag

-       1000ml Cylinders

-       Pestle and Mortar

-       Sieve

-       Rubber Gloves

-       Mixing Rod


I must state, buying silver nitrate power can be quite costly but it is readily available. Luckily for me working in a photography department, I just happened to have three small bottles in stock (insert smug face). Most of the materials needed to create soil chromatography can be found in any home store or supermarket at a low cost.


With this first run of S.C prints being a test batch, I used a soil sample from my garden. I was also under the impression that this may or may not turn out as seen in journals, but I was ok with that due to this being a new process I was exploring.


To start with I had to prep the filter paper with a light sensitive solution and that came in the form of mixing silver nitrate to water. I placed 1gram of silver nitrate into 300ml of water and mixed this within a cylinder until no silver nitrate powder was visible. I poured equal amounts of this silver nitrate mix into petri dishes. The petri dishes sat in disposable paper plates. I used the paper plates as support for the filter paper to stop any sagging once the filter paper had solution running through it.


Preparing the filter involved several steps. Solution would absorb and run through, and I did not want any silver nitrate solution running to the filter edge. With S.C, the outer rim tends to spike and so a border is needed to support the spike and for it to not bleed off the paper edge. I therefore found the centre point of the paper and working outwards made two small pencil marks at 4.5 and 5.5 centimetres. The first mark closest to the centre would be a guide for the silver nitrate solution to run to and the furthest mark a guide for the soil solution to run to. With the centre point, I poked a 3mm hole through the paper and created a small filter with a separate piece of filter paper. This filter sat within the centre with one end of the filter predominantly sticking further out of the paper at one end. Once the paper was marked up, I sat the paper centrally within the petri dish and allowed for the silver nitrate solution to soaked through and disperse across the surface. When the solution hit the first guide mark I carefully removed the paper and filter and placed it into a light tight dark bag to soak for twenty-four hours. This process was repeated across eight filter paper pieces.


The third step was to dry the soil sample out so that it could be broken down easily. I ‘cooked’ the soil in the oven and once cooled, placed several teaspoons into a pestle and mortar. I crushed the soil sample into a fine grain powder, which was sieved through and re-crushed. By breaking the soil down to a fine grain, I could help the soil mix easily with the sodium carbonate and water solution and remove any other unwanted materials. The mixing of soil with sodium and water would take several hours to complete. This step of the process involved agitating the soil with sodium and water on the hour allowing for a true breakdown of soil particles and infusion with the liquid solution. I decided to agitate for twenty-four hours alongside the now light sensitive filter paper.



The next day, I set up several petri dishes inside of paper plates again but this time the petri dishes would contain the agitated soil solution. I recreated new filters to replace into the centre of each filter paper and then placed them into the solution. Once again the reaction was instant, and the soil solution began to absorb through the paper until after several minutes it reached the outer guide mark. When each piece was soaked through to the guide mark, I placed the paper onto a towel at a window and allowed for the reaction to occur between indirect sunlight and light sensitive paper. The development period had begun and from my reading, it was advised to add a little heat to the room in which the developmental process was taking place. I switched on my small heater and let the process act out. This development process would take up to seven to ten days to fully evolve and complete. I decided to go with seven days before I removed the S.C from the window and began documenting each outcome. Over the course of the seven days, I studied the developmental process, and watched the soil react to the light sensitive chemicals infused within the paper. Marks appeared in circular arenas and at multiple points. Sharp lines shot out from the centre reaching towards the end marker point and curved flake ends would eventually appear demonstrating a spike in activity.



From the imagery above, you can see the initial outcomes I created. On first impression I am pleased that experiment worked and that a picture had developed. When looking I can identify where solution had caught areas of the paper and so I must be more careful when handling and moving the filter paper as it is very sensitive to any solution. The important factor is that of the soil sample picturised on the filter paper. A clear reaction has occurred which evidences a living system within the soil sample broken down. As these were test pieces and I was successful in what I had created, I knew I could move forward and filter this work into my field research. It was with this that I began planning my next day residency out in the North Yorkshire Moors (see Goathland blog).


On my return from Goathland I began to prepare my filters for distributing soil solution through. As this was a time-consuming factor, I firstly placed my soil samples out into three separate trays to dry up within the sunlight. During this drying period, I then began the mixing of silver nitrate and water. Instead of placing 1gram of silver nitrate into 300ml of water, this time I increased the silver nitrate mix to about 1.5grams and mixed this within the same 300ml ratio of water. Once again this all occurred within a cylinder and was mixed until no silver nitrate powder was visible. With the solution mixed and the filter papers coated, they entered the dark bag and due to space restrictions (I made x16 filter pieces) I had to place four filter papers into a ‘not so light tight’ black bin bag. This black bin bag allowing light in would have a different effect on the light sensitive solution later on within the project.



The next day, I examined the soil samples collected and unfortunately they had not fully dried out and so I placed each sample onto different baking trays. I switched the oven on and ‘cooked’ the soil for around the time I smelt a burning taste in the air… I did not realise how easily soil would cook and at a quick rate (ignorance on my part). After a slight dramatic moment within my kitchen the soil samples were out and cooling down so that I could work with them. As I was using three different samples from one walked residency, I made sure to mark each tray 1 – 3 and each filter paper depending on which soil had fused through. This would also support final analyse at the end development point. From the pictures above you can see the samples dried and ground down through the use of a Pestle and Mortar. These were again placed into a cylinder and soda was applied along with water. To help finish the soil sample in preparation from soda and water application, I used a sieve to filter out any last unwanted elements. Once mixing was completed, I played the waiting game of around eight hours to allow for the soil to break down as much as possible within the cylinder solution. After such a lengthy period of time I set up many petri dishes and plates to begin the solution application to the filter paper. The same reactions occurred with each material, and I followed the solution up to the 5.5-centimetre mark. When removing the filters, I made sure to allow no solution to spill onto any part of the paper.


Location Sample #1 - 0.873v


Location Sample #2 - 0.909v


Location Sample #3 - 0.946v


For this section I will discuss the appearance of the soil chromatography outcomes and in the latter sections of this text I will analyse samples within a scientific perspective.I left the filter paper to dry and develop through exposure to indirect sunlight over the course of several days and the outcomes have been excellent. Each soil sample has infused and reacted very well with the silver nitrate solution causing a clear reaction. I believe that increasing the silver nitrate measurement by 0.5 grams has enabled a stronger chemical reaction. It has caused a slight darker appearance with the soil’s brown tones, but the papers placed within the bin bag had produced a lighter tone (something to consider).

In the above galleries I have split each soil sample up so that a clear distinction can be made between each sample outcome. It is evidenced within each sample that reactions have occurred with the soil and that appearance of each sample has come across as an active sample demonstrating clear living organisms. A circular formation is present with several small ‘circular’ sections within. Some showcase lines drawn from the centre point whilst some lines only appear at the outer edges, softly (almost like the underside of a mushroom spore). A fine wall appears on the edge of some samples as a complete circular whole whilst some samples only evidence small spot like formations. Each sample although has several similarities, they are all their own unique outcome. Within the following section, I will breakdown each chromatograph feature and parameters to quantify soil quality, and living micro-organism system.


The following abbreviations are used to support chromatograph features:

  • OZ - Outer Zone

  • MZ - Median Zone

  • CZ - Central Zone

  • SP - Spikes

  • CH - Channels

  • COL - Colour

  • R - Rings


The following abbreviations are used to support chromatograph COLOUR features:

  • Y - Yellow

  • BL - Blue

  • LBL - Light Blue

  • DBR - Dark Brown

  • MBR - Medium Brown

  • LBR - Light Brown

  • W - White

  • G - Gold

  • GR - Green


Location Sample #1 - 0.873v


OZ - 2mm

MZ - 12mm

CZ - 4mm

SP - 140

CH - 0

COL - Y, BL, MBR, LBR, DBR

R - 6









Location Sample #2 - 0.909v


OZ - 3mm

MZ - 31mm

CZ - 11mm

SP - 64

CH - 74

COL - G, Y, BL, MBR, LBR, GR, LBL

R - 7









Location Sample #3 - 0.946v


OZ - 8mm

MZ - 34mm

CZ - 10mm

SP - 70

CH - 74

COL - W, BL, DBR, MBR, LBL

R - 10








Sample Conclusion

Sample #1, 0.873v - Lowest (excess saline = low pH level)

Sample 1 demonstrated the lowest scores across five of the seven parameters. The OZ measured at a 2mm cloud stating that very little bacterial activity was present. MZ at 12mm indicated a protein and organic carbon presence but against samples 2 and 3, it scored 50% lower. The 50% lower measurement against sample 2 and 3 was also evident with the central zone. Channels were unreadable and therefore scored at 0 giving no indication to an increase organic matter. Spikes were read at 140 which suggests that organic matter and nutrients are present which contradicts the channel reading (unreadable measurement error). Ring counted at 6, which reads just below the mean average however with a gold coloured ring indicates some healthy soil present.


Sample #2, 0.909v

Sample 2 demonstrated a mid-range score across all seven parameters. The OZ measured at a 3mm cloud stating that very little bacterial activity was present but was 1mm greater than sample 1. MZ at 31mm indicated a protein and organic carbon presence which was at an increased 19mm than sample 1. The 50% greater measurement against sample 1 was also evident with the central zone which measured 11mm. Channels were measured at 74 indicating an increased organic matter and nutrients present. Due to the channels crossing across all 7 ring zones indicated that an integration of soil components had occurred. Spikes were read read at 64 which suggested that organic matter and nutrients were present but this reading put the sample at 75% lower than sample 1. Spikes were much more defined but did not exceed the clarity of sample 3. Ring counts were at 7, which again just read just below the mean average (8). The colour range was a mixed measurement demonstrating healthy microbial activity and unhealthy activity.


Sample #3, 0.946v

Sample 3 produced the healthiest readings across six of the seven parameters. The OZ measured at an 8mm cloud stating that bacterial activity was present. MZ at 34mm indicated a protein and organic carbon presence and against sample 1 and 2 it read highest. The central zone did indicate a 1mm short fall against sample 2 but with such a small measurement it did not effect the production of a good healthy body of nutrients. Channels were equal to sample 2 evidencing a increased presence of organic matter and nutrients. Channels crossed through 9 ring zones displaying integration of soil components. Spikes were read at 70 which suggests that organic matter and nutrients are present. Due to a clear and elongated spike patterns this indicated that the soil was healthy. With such clear spikes when compared to samples 1 and 2, sample 3 read as the healthiest. The colour range was a mixed measurement demonstrating healthy microbial activity and unhealthy activity.


By analysing soil samples in such a scientific manner, enables me to evidence an invisible natural activity occurring across multiple landscapes. Through the use of soil chromatography I can possibly cross examine soil activity against feelings and sensations found within landscape aesthetics. This possible categorisation of feelings and sensations through soil samples could prove complex but there is a possible chance of working in this method. To add further development the soil samples act as the invisible representative of natural elements within the functional fit model. The functional fit model is a landscape model I currently explore my research within.


A question for me is how to display such a fine detailed series of images to an audience. As with all blog entries, I am disseminating to an audience digitally, but what about in person and in the gallery setting? I took these images to work and placed them upon one of the display walls. I wanted to display the soil chromatography to audiences to understand how they could be shared and displayed. A traditional display of wall placement was chosen, spreading the samples out into a singular and then as a double line. The singular line demonstrates a connection to the residencies walk/drift with a start and end point and between points a collection of living organisms moving between a 'space'. The 'space' for exhibition’s sake is two points on a wall but within the north Yorkshire Moors landscape there is a 'space' that has been collected, extracted and formulated into something tangible for the viewer to connect and analyse. Presenting the S.C as a double row worked well and I felt had a stronger presence and place when situated on a flat wall. Each sample could work with each other from four points rather than a singular linear pathway. It does negate the notion of a walk due to a compact hanging but some factor of the walk can be suggested with a horizontal positioning. A group placement of each sample presented in three sections can also demonstrate each location point from the walk within the landscape. The viewer can move from point 1 through to point 2 and end with point 3. A viewer traverse between locations and enables an experience with the soil chromatographs that indicate the quality of each landscape location point.



 As the research progresses, I will look to utilise soil chromatography as a support method for visual analyse when working with invisible materials. The next step will now be to digitally manipulate the scanned imagery in an attempt to pull out depth and texture.

 





 

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