In the spirit of photographic experimentation, the “aloetype process” emerged from over a decade of creative inquiry into plant-based image-making. Aloe produces warm, tan-to-yellow negative images using just three simple ingredients: aloe, vinegar, and baking soda. It’s a mostly nontoxic, accessible process that works on a variety of absorbent surfaces, making it ideal for artists, educators, and alternative photography enthusiasts seeking sustainable, low-tech methods.
How the process differs from ordinary anthotypes
“Aloetype” is an anthotype with a twist. While it still relies on plant material to form an image, it introduces a simple chemical modification to set it apart. Instead of using pigments from petals or berries, this process uses compounds from the outer layer of aloe leaves, combined with vinegar to extract the active agents. Just before coating the paper, baking soda is added to neutralise the acidity, which increases the contrast of the resulting image. The process produces warm-toned, negative images. This is unusual since most anthotype processes produce positive images. Fruits can sometimes result in negative anthotypes due to oxidation.
This article summarises the process I’ve developed for making anthotypes with aloe plants. Aloe-based anthotypes form a strong image after an exposure of only 15–20 minutes. (Sensitivity decreases during exposure, so longer exposures will have less and less effect.)
Aloe is mostly nontoxic, although recent findings by the National Center for Toxicological Research and the National Center for Complementary and Integrative Health indicate that you might want to be careful working with aloe.
“I’ve been using the same aloe plant for years, just taking little pieces off of it here and there.”
After a visit to the University of California Botanical Garden, I concluded that the plant I’m using is probably an Aloe arborescens. Other species may work too.
I prepare my anthotype emulsions using vinegar as a solvent: smashing up the aloe thoroughly and then letting it steep in vinegar for at least two days. Longer brewing times may improve image quality. The aloe-vinegar solution has a shelf life of 3–4 weeks.
I usually use 5–10 mL of 5% white vinegar for a 4- to 7-cm-long piece of aloe, which is more than enough for one or two 5 x 7″ prints. You don’t need a lot — it takes less than 0.1 millilitres of vinegar to coat a square inch of paper.)
The active ingredient for this process is in the outer layers of the plant, not in the gel. The process still works if you scrape the gel off before preparing the sensitiser (though you don’t have to do that, and I usually don’t bother.)
Before making a print, I neutralise the vinegar with baking soda. The aloe solution appears to lose most of its sensitivity between 24 and 48 hours after being neutralised. The more acidic the solution is, the lower the image contrast will be, so it’s better to add too much baking soda than too little.
You don’t need much baking soda either. It takes roughly 1/16th of a teaspoon of baking soda to prepare 2 millilitres of sensitiser.
Using alcohol as a solvent may work too, though I haven’t tried this. Using water as a solvent doesn’t work well—the resulting emulsion tends to get mouldy and generally seems to produce worse results.
I usually make my anthotypes on watercolour paper. I have also used wood, cardboard, and fabric with some degree of success, though the contrast of the resulting prints was rather low. The type of paper or other surface used has a significant effect on image contrast.
Most of the time, I expose my anthotype paper right after applying the sensitiser, while it’s still wet. I have also coated paper and then successfully printed on it the next day, after the paper had dried. (It doesn’t work well if you wait longer than 1 day, probably because of the sensitivity loss noted above.) You can even coat paper once, let it dry in the dark, and then coat it again to get an extra-strong image.
Rather unusually for anthotypes, the aloe-derived images are negatives rather than positives—the aloe-based emulsions darken in response to light. Some other anthotype formulations do this too. Malin Fabbri has informed me that certain types of berries and flowers also produce negative images, here is an example of Black swallow wort (Vincetoxicum louiseae) anthotype by Anne Eder and Eucalyptus (Eucalyptus camaldulensis) anthotype by Patricio Ceriani.
This is interesting because it indicates that these anthotypes may rely on a different kind of chemical reaction. This has led me to the opinion that the term ‘anthotype’ is best thought of as a category, rather than a single process. Hidden within that category, there is a wide diversity of plant-derived photochemistry.
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