The chlorophyll process is an organic alternative photography process akin to the anthotype process. However, instead of printing on the crushed extract of fruit or plant matter, the prints are bleached by sunlight directly onto the surface of leaves using a positive. The resulting images are stunningly delicate and beautiful, ranging from haunting silhouettes to crisp definition. Despite the simplicity of the finished product, the process itself can be tedious with plenty of trial and error.
For the purpose of this study the following question(s) were addressed:
- Is there a particular type of leaf needed to carry out this process?
- Do I need consistent bright sunshine for the process to work? i.e. if it’s too cloudy will it not work as well?
I predict that only particular leaves will work for this process, i.e. tropical leaves will probably work best as the leaves are not sprouted on the trees yet and the leaves that are around have survived the winter, thus unable to withstand the chlorophyll process.
The willingness to experiment with varying sunlight, exposure times and different leaf specimens it can be a fulfilling and humbling way of engaging the natural world in craft. British artists, Heather Ackroyd and Dan Harvey were among the first to define the Chlorophyll Process, though, in a slightly different format. They developed a method of projecting an image onto grass using a negative and light cast by a projector bulb after noticing vague outlines of a ladder cast onto one of their “grass installations”. The range of contrast of the negative denied or allowed light to reach certain areas of the grass surface resulting in the bleaching of the light deprived areas.
Ackroyd & Harvey’s work has been exhibited in contemporary art galleries, museums and public spaces worldwide; sculpture, photography, architecture, ecology and biology are disciplines that intersect in their work, revealing an intrinsic bias towards process and event. Often reflecting environmental and scientific concerns, they are acclaimed for large-scale interventions in sites of architectural interest, acknowledging political ecologies by highlighting the temporal nature of processes of growth and decay in the urban space. Interaction with scientists is often key to Ackroyd & Harvey’s practice with ground-breaking research initiated over fifteen years ago with the Institute of Grassland and Environmental Research (now IBERS). Currently the artists are developing a series of new artworks for the University of Cambridge in response to working closely with the Department and Museum of Zoology and the Cambridge Conservation Initiative.
Binh Danh is an artist of national importance with work that investigates his Vietnamese heritage and our collective memory of war, both in Viet Nam and Cambodia—work that, in his own words, deals with ‘mortality, memory, history, landscape, justice, evidence and spirituality.’ His technique incorporates his invention of the chlorophyll printing process, in which photographic images appear embedded in leaves through the action of photosynthesis.
Bleaching occurs when a photon has enough energy to completely free an electron form its atom, becoming an ion with a net positive charge. Higher light intensity equals a higher concentration of ions, resulting in a surface which has the ability to react with the oxygen in the air. This reaction causes the bleaching of the surface.
Leaves of your choice (broader and flatter are easier to work with)
- Positive / transparency (higher contrast preferred)
- Contact printing frame / sheets of glass
- Scissors / gardening stem cutter
- Newsprint / blotting paper
- Optional – You will need a way to provide the leaf with water if you want an even longer exposure. Small plastic bags and rubber bands work if you tie them around the stem securely (I use florist stem water tubes).
- Optional – UV stabilized polyester resin to cast the finished piece (Binh Danh’s recommendation.
Step 1: Choose your leaf.
As noted, broader flatter leaves are easier to work with (spinach, maple or oak for example). This is a great way to engage your local environment, visit a park or your backyard! Think about how the leaf would add to your piece, either in composition or subject matter. Also, when cutting your sample, for transportation and preparation, cut the stem at an angle, leaving as much of the stem as possible, and immediately place the end in bag or bottle of water.
Step 2: Choose an image and create your positive/transparency.
Higher contrast of your positive with help with the overall clarity of your results though it is possible to achieve a wide spectrum of mid-tones.
Step 3: Arrange the positive on the leaf and sandwich both together in the contact printing frame or pressed tight between sheets of glass.
This is the tricky part of the process as you are dealing with a living organism. A contact frame works well as it presses the leaf flat for a solid and easy exposure. However, if you want to attempt to keep the leaf from drying out and dying for an even longer exposure, you’ll need to provide water. For this, I’ve found that pressing between glass sheets or a glass sheet and a masonite board works well. It is a more tedious set-up to fasten/tape the sheets together so the positive and leaf are as flat as possible, but you can position the leaf and positive so that the stem hangs out one side. This will allow you to secure a small bag of water to the stem tied tight with a rubber band. As noted, I use florist water tubes and periodically have to refill the water.
Step 4: Place in an area of direct sunlight.
As noted, sunlight intensity affects the rate of bleaching and the overall results. As a result, the time of year and geographic location will also have an impact on your prints.
Step 5: Checking and removing your print.
After at least 24 hours of direct sunlight, carefully check on your print to see if the bleaching process is occurring. As the leaf may have changed colour overall due to drying, remember to let your eyes adjust to the colour and texture of the leaf as chlorophyll print images can often be ghost like and vague. The leaf may also be thin, delicate and slightly moist. Thus, peel back the positive very slowly when removing it. Place the leaf in between newsprint or blotting paper to dry off.
Step 6: Preserving your Chlorophyll Print.
As this is a natural process, the sun’s bleaching power will continue to affect the leaf until it’s dry and brittle. From my experience, the image is not lost entirely over the years, but you do lose some of the crisp clarity. When not on display, press your leaf in a book to keep it flat and out of direct sunlight, remembering to use extreme caution when removing it for show. It is also possible to cast your leaf in a ¼ to ½ in layer of UV stabilized polyester resin (link above). Once the casting is completed, the print can be mounted and displayed without fear.
Creating my own Chlorophyll Images:
Firstly I tried this process with leaves found in my garden that would probably prove harder to bleach in the sun, so as predicted this process was ineffective in changing colour. Also the weather conditions are not very sunny at this time of year resulting in little or no sunlight. My first attempt was unsuccessful, I believe, due to the type of leaf used. I used a transparency and secured the leaf between two pieces of glass, with a feeding bag. However, the leaf was exposed to the sun through the window for approximately one week and the weather conditions was cloudy with rain. On evaluation maybe placing the leaf inside behind the window assisted the process to fail. Possibly direct ultra violet (UV) light without any extra barriers could have resulted in some discolouration.
I tried the same method again but this time I didn’t secure the leaves with feeding bags in hope that the leafs would dry out whilst exposing in the sun resulting in the leaf having some discolouration. However, again this technique was unsuccessful but upon evaluation I have not fully re adapted my technique. I am now almost certain that a tropical leaf is needed for this process, I now believe that this requires purchasing a shop bought plant or visiting a florists to request leaves that would be suitable for the process.
This process was unsuccessful due to insufficient amount out of time, with other projects being more demanding and due to the time of year there were no deciduous leaves available so my attempts with evergreen leaves were unsuccessful. The chlorophyll process is in fact similar to the anthotype process in that it is a pigment sun bleaching method. This time however, the pigment happens to be green and named chlorophyll and is distributed throughout the leaf, or just like an Anthotype, be painted on paper. I would like to revisit this process at a more suitable time of year, when large deciduous leaves are available, or a chlorophyll extraction could be performed to paint a canvas.
 ADVANCED TONING PDF, (2016). Berk-Edu: Advanced Toning. [Online] Available from: http://www.berk-edu.com/ADV_subsite/PDF_adv/ADVbook_toning.pdf [Accessed: 08 May 2016]
 ACKROYD AND HARVEY, (2016). Works. [Online] Available from: http://www.ackroydandharvey.com/ [Accessed: 22 March 2016]
 ALTERNATIVE PHOTOGRAPHY, (2000). The Chlorophyll Process. [Online] Available from: http://www.alternativephotography.com/wp/processes/chlorophyll-process/the/chlorophyll/process %5BAccessed: 22 March 2016]
 UNIVERSITY OF CAMBRIDGE, (2016). Speaker Spotlight: Heather Ackroyd and Dan Harvey. [Online] Available from: http://www.sciencefestival.cam.ac.uk/speaker-spotlight-heather-ackroyd-dan-harvey [Accessed: 22 March 2016]
 ZAVOS, A. (2011) Binh Danh’s Photographs Appear Embedded In Leaves Through The Action Of Photosynthesis. Feature Shoot. [Online] Available from: http://www.featureshoot.com/2011/09/binh-danhs-photographs-appear-embedded-in-leaves-through-the-action-of-photosynthesis/ [Accessed: 22 March 2016]