Turmeric Anthotype Tutorial: Make Botanical Sun Prints with Curcumin

What Is an Anthotype? Where Does It Come From?

An anthotype is a photographic printing process that’s entirely natural, eco-friendly, and genuinely fascinating. It uses natural substances, plant extracts, flower petals, or vegetable juices, as the light-sensitive emulsion instead of chemicals. Anthotype was first developed in the early 19th century as a way to preserve images on paper without any chemicals at all. Today it’s experiencing a real resurgence, thanks to its eco-friendliness and the unique, organic results it produces.

If you’re a fan of traditional printing techniques and natural materials, anthotype printing might be right up your alley. One of the easiest plant extracts to work with is turmeric powder, also known as curcuma powder.

Turmeric is a spice commonly used in Indian and Southeast Asian cooking. It comes from the root of the turmeric plant, dried and ground into a bright yellow powder. Beyond the kitchen, turmeric has also long been used for medicinal purposes, and even as a dye.

• A newspaper or a trash bag to protect your work area
• Gloves, to keep the stain off your fingers and work surface
• Turmeric powder
• Thick paper in a few different types and textures to experiment with
• Denatured alcohol
• 2 glasses
• Paper towel
• Paintbrushes
• A glass plate (a picture frame is perfect)
• Clips or clothespins to hold the glass in place (binder clips, bulldog clips, and regular clothespins all work fine, whatever sturdy clip you have on hand)
• Borax

Add two tablespoons of turmeric to a glass, then add the denatured alcohol and mix well. The alcohol releases the pigment, curcumin, from the powder. Stir thoroughly to make sure it’s evenly mixed.

Strain the mix to remove any leftover powder. A coffee filter or a piece of strong paper towel works well to catch all the solids, this keeps the pigment evenly distributed through the liquid.

Use a paintbrush to generously coat your paper with the turmeric mixture. A light-colored, thick paper with plenty of texture gives the best results. Coat all the way to the back edge for an even effect. If you want full edge-to-edge coverage, use a larger frame so the clothespins sit outside the print area rather than on top of it.

Put your coated papers somewhere dark to protect the pigment’s vibrancy, a card box works well, kept away from bright light and direct sunlight. While it dries, go hunt for interesting flowers and leaves, fresh foliage or pressed and dried both work.

Lay your chosen plants on the coated paper, place a glass plate on top, and secure it all together with a few clothespins or binder clips, whatever you’ve got on hand works. Expose the glass plates next to a sunny window or outside in direct sun, making sure the paper is secure and won’t shift or fall. Keep in mind the clip itself blocks the sun exactly like the plant does, and will show up in your final print.

Leave the paper in strong, direct sunlight for about 5 hours in summer, depending on how intense the light is. It’s fine to expose over multiple days as long as the plants don’t move, you’ll see the pigment darken as it develops.

If you’d like to see two intensities in the same print, try layering glass: expose the first plant, then add a second plant and expose again.

Once you’re happy with the depth of color, remove the clips or clothespins, lift off the glass, and take the flowers or leaves off the paper.

To reveal the result, you’ll need borax (or a borax substitute), water, a spray bottle, and a spoon. Dissolve 2 teaspoons of borax into the water and stir until fully dissolved, then pour the mix into your spray bottle and shake. Spray the solution directly onto your paper to reveal the plant contrast underneath. Alternatively, dip the paper into the borax solution for a few seconds until the result appears, don’t leave it in for more than about 20 seconds, or the fine detail will start to disappear.

Borax, chemically known as sodium borate (or sodium tetraborate, Na₂B₄O₄·10H₂O), is what shifts your print from yellow to that rich reddish tone. In the US it’s still sold freely as a household product. In the EU and UK, it’s a bit different: borax is no longer sold to the general public there, so you won’t find the real thing on supermarket shelves.

What you will find instead is a product usually labeled “Borax Substitute.” It’s not the same chemical, it’s sodium sesquicarbonate, but it’s widely available in hardware stores and online, and it works just as well for this technique. If you want the real thing, pure borax can still be ordered online in most of Europe, just not off the shelf in person.

Can’t find either one? You can make your own. Sodium sesquicarbonate is simply equal parts washing soda and baking soda, two different products, so don’t mix them up at the shop:

• Washing soda (sodium carbonate, Na₂CO₃), sold in the laundry aisle of most supermarkets, sometimes labeled “soda ash”
• Baking soda (sodium bicarbonate, NaHCO₃), the one you already have in your kitchen cupboard

Mix one tablespoon of each with your water and you’ve made the same compound that’s in the store-bought “Borax Substitute,” not an approximation, the actual same thing. If you can’t find washing soda either, you can make that too: spread plain baking soda on a baking tray and bake it at 200°C (400°F) for about an hour, the heat converts it into washing soda.

Can I just use baking soda on its own, skipping the washing soda? Not quite as well. Baking soda alone is noticeably milder and less alkaline than borax, so it will shift the color somewhat, but not as strongly or as reliably. If baking soda is genuinely all you have, it’s worth a try on a test strip first, but for the vibrant red tone shown in this tutorial, real borax, “Borax Substitute,” or the homemade washing soda + baking soda mix is what we’d recommend.