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!