The chlorophyll printing process works by letting a leaf receive an extraordinary amount of UV light to force a pigment change while the leaf is alive. There is very little information about this process on the internet and much is inaccurate. Guide yourself by this blog to avoid getting confused.

Most leaves have a variety of pigments that can absorb and release energy from a wide range of wavelengths, these are chlorophyll pigments, carotenoids and anthocyanins. Pigments capacity to absorb and dispose of energy is crucial to keep plants’ photosynthesis mechanism undamaged.

Anthocyanins do not intervene much in photosynthesis so they are irrelevant to us.

Chlorophyll pigments, the green ones, absorb UV light and reflect back to us green light, and can convert light energy into chemical energy, these are the main pigments intervening in the photosynthesis of the plant. However, they do not help to release any energy excess, so if the plant receives too much UV light, only carotenoid pigments can intervene.

Carotenoid pigments absorb less UV light and more violet and blue-green light. They can reflect yellow, orange and sometimes red light to us. Carotenoids are present on plant leaves, but we often don’t see them because chlorophyll pigments are more abundant, therefore masking any other tone. Carotenoids play an important role in absorbing light when there is less UV available (autumn), but they also play a crucial role when there is too much UV available.

When we leave a plant or a leaf in full sunlight (like when we forget a plant by the window sill), it is receiving a huge amount of energy, if that is not handled properly, it can damage the photosynthetic machinery. Carotenoid pigments have the capacity to dissipate any energy excess as heat as they are able to convert chemical potential energy into vibrational energy.  In order to keep a healthy UV diet and preserve the photosynthesis mechanism the leaf changes its pigments and gets rid of the energy excess. It is a survival strategy.  When we leave plants by the window and we see them turning lighter green or even yellow, this is not because the plant is drying or dying, it is because the plant is forcing a pigment change to cope with the overdose of sunlight.

When we are using the chlorophyll printing process, we are forcing this pigment change. We are not letting a leaf drying out, that would result in brown, curly and very fragile leaves instead of any print.

 


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This is a list of small changes I did while I was researching this process and that had a big impact on my research.

0. Select the right plant

Not all plants work, it depends on their structure. Some plants can easily cope with high levels of UV light without forcing any pigment change, such as palm plants, aloe-veras, jade plants and snake plants. Other plants, won’t activate their survival mechanism and they simply let their leaves dry and some have visible carotenoid pigments (because they are the dominant!) such as Pink Princess plants. (Read previous posts if this sounds confusing)

1. Plan “the cutting”.

Cut the leaf from the plant only when you are about to expose it to sunlight.

You can only force the pigment change by overfeeding a leaf while it is still alive with extraordinary amounts of UV. If the leaf dries it won’t record any image.  You will need to plan “the cutting” according to the weather forecast, and only take it into action when you are ready to go.

2. Start the exposure at 11 am on a summer sunny day.
This is because of the same principle mentioned above.  If the leaf dries it will become brown and curly and it won’t replace any chlorophyll pigments by carotenoids, so it won’t record any image. 4 cloudy days can easily ruin your printing.

3. Print the same image on two separate acetates

By printing twice the same image you will win contrast on your final print. If you have two layers of one same image placed on the top of each other, the ink pigments on the top acetate (top layer) will protect from the sunlight the ink pigments on the acetate underneath (bottom layer).  Sunlight will bleach the ink pigments on the acetates at the same speed it forces the pigment change on the leaf, so in order to keep good contrast you can double up the layers. Just make sure you line up the two acetates rightly. Otherwise, you might end up with a blurry image.

4. Make sure the light hits the frame straight.

Orientate the frame so it intersects with sunrays forming a right angle. The frame should always be parallel to the sun: When the sun is high, (noon) the frame should be flat against the floor but when the sun is low (7:00 PM), the frame should be perpendicular to the floor and facing the sun. Make sure that sun rays are always hitting straight your printing frame, and not from an oblique angle. This plays an important role in getting the pigment changed before the leave dries.

5. Make sure there is enough pressure between the acetates and the leaf.

The amount of pressure between the acetate and leaf will determine how sharp or blurry looks the final print. The more pressure the sharper the image will be. If your clipping frame or your printing frame does not provide enough pressure, make sure you place some paper or fabric on the back of the leaf.

6. Mix the fixer when the exposure has finished.
When clear areas have changed from green to yellow is time to end the exposure. At that precise moment, you’ll need to immerse the leaf in the fixer.

Otherwise, the leaf will dry and curl. Here again, you’ll need to calculate the date that you’ll finish the exposure and prepare for it. The chlorophyll process is simple but requires planning and dedication.

This series of posts including the step by step video should guide you towards successful prints!

Good luck!


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MATERIALS

– Contact Printing frame. Clip frames will work too or any piece of glass + pegs to flatten transparencies against the leaf.
– Sunlight. You can’t use a UV lamp
– Plant leaf
– Copper sulphate
– Distilled water
– Scale
– Plastic teaspoon
– Measuring jug
– Developing tray
– Digital Transfer film.
– Printer
– Gloves

BEST PLANTS

Aspidistra (Normally called cast iron plant, and it will take about 3 weeks to print. However, it’s the most archival plant)
Colocasia (Exposure times of about 4 – 6 hours on a sunny bright summer day)
Hosta (Exposure times of about 4 – 6 hours on a sunny bright summer day)
Alocasia (Exposure times of about 4 – 6 hours on a sunny bright summer day)

Use: green flat leaves from shadow tropical plants with no patterns. Araceae normally works very well.

Avoid: Evergreen plants and variegatas and some of the families described below.

Spathiphyllum- Also known as Peace lily. This plant belongs to the Araceae family, which is often very appropriate for chlorophyll printing. Its big green flat leaves, which might occasionally turn yellow, made me believe this lily was perfect to work with. However, the outcome was really disappointing. First of all, it takes a lot of time to get any outcome with this plant,  and then, the resulting prints, lack of contrast and definition.

Philodendron imperial- Philodendros are a dysfunctional family. While some of them are absolutely fantastic for this process such as philodendron selloum and philodendron giganteum, the royal branch from this family are terrible for chlorophyll printing; avoid using philodendron imperial and pink princess.  Climbing philodendros are also pretty bad, including scandens and elongatum.

Devil’s Ivy –   Ivy tends to work very well for chlorophyll printing.  You might be able to get a quite good print in 2 Summer sunny days. Its green flat leaves are very convenient. It is very easy to source Ivy leaves from the streets and I used to think Ivy was the most convenient plant for the process until I came across the Devil’s variety. It just doesn’t work at all!

 

 


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This blog post is about 2 things that didn’t work. Realising that I could cook the leaf instead of forcing a pigment change had a very strong impact on my research.

I hope you enjoy my archive of failures and that it saves you some time if you decide to practice this process. Enjoy!

 

UV lamps

UV lamps release very little light compared to the Sun, and they mainly release UVA light. In order to force a pigment change on a leaf, one needs UVB light mainly as well as large amounts of visible light. If you use a UV lamp, it will cook your leaf, as these lamps release much more heat than light!

Black back printing frame

The majority of the photographers working with printing process use printing frames with black backs.  It doesn’t work for this process as it helps to raise the temperature, and again it will cook the leaf in your printing frame rather than bleaching it!

I hope sharing my research journey with you was useful and encouraging :)


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Yesterday’s workshop was attended by 300+ people. 226 people view the workshop on Facebook and 90 people view on Instagram!

Thank you all, I hope it encouraged you to try this organic photographic process!


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On Thursday 2nd of August from 11:00am to 12:30,  I’ll be running a free online chlorophyll printing workshop, with the support from the Professional Development bursary from a-n.

This event is free an open to all artist, but registration is mandatory. You can learn how to print images directly on leaves by signing up here

 


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