Cyanotypes are known for their rich Prussian blue—crisp, cool, and unmistakable. But with a little gentle chemistry, you can shift that iconic blue into warmer, moodier hues: soft sepias, deep charcoals, even plum purples. The process is called toning, and it’s as much about art as it is about science—a way to bring new atmosphere to your prints.
How Toning Works
Toning is a two-step transformation:
- Bleaching lightens the Prussian blue, breaking down the ferric compounds.
- Tannin-rich toning reintroduces colour, as natural tannins bind to the print’s surface, replacing the blue with earthy browns, smokey greys, or dusky violets.
This isn’t harsh chemistry—it’s a slow, hands-on process often using ingredients from your kitchen: tea, coffee, red wine, or even pomegranate skins.
What You’ll Need
- A finished, well-rinsed cyanotype print
- A shallow tray or basin
- Bleach bath: 1–2 teaspoons of washing soda (soda crystals) (sodium carbonate) dissolved in about 1 litre of water
- Toning bath: Strongly brewed black tea, coffee, or other tannin-rich liquid
- Clean water for rinsing
- Gloves (recommended)
Step-by-Step Guide
- Bleach: Place your dry cyanotype print into the washing soda bath. Watch closely—within 30 seconds to 2 minutes, the deep blue will fade to pale yellow or light green. Remove promptly.
- Rinse: Gently rinse the print in clean water to halt the bleaching.
- Tone: Submerge the print in your chosen tannin bath. Let it soak—anywhere from 10 minutes to an hour—until the colour shift reaches your liking. Tea often yields warm browns, coffee gives soft charcoals, and certain teas or plant dyes can bring purples or pinks.
- Final Rinse and Dry: Wash the print in clean water, then lay flat to dry, away from direct sunlight.
Quick Toning Chart for Beginners
| Ingredient | Likely Hue Shift | Notes |
|---|---|---|
| Black tea (strong brew) | Warm sepia brown | Classic, reliable results |
| Coffee (strong brew) | Charcoal grey / soft black | Rich, muted tones |
| Green tea | Pale olive / yellow-brown | Subtle, delicate effect |
| Red wine | Purple-brown / burgundy | Can vary with paper type |
| Pomegranate skins | Plum-purple | Needs longer toning time |
| Hibiscus tea | Pinkish-purple | Best on lighter bleached prints |
Tips for Best Results
- Different papers and teas produce different tones—experiment!
- Avoid over-bleaching, as it can damage the paper fibres and image detail.
- Layering tones (e.g., tea then coffee) can produce complex, unique hues.
Toning cyanotypes is an invitation to play—each print develops its own personality. What starts as that crisp Prussian blue can transform into something softer, older, and richer, carrying the memory of both light and time.
Printing Cyanotypes on Fabric
- Fabric choice: Natural fibres (cotton, linen, silk) work best because the cyanotype solution chemically bonds to cellulose or protein fibres. Synthetic fabrics don’t hold the image well unless they have a natural-fibre blend.
- Fabric prep: Wash the fabric first (no fabric softener) to remove sizing and oils — this ensures better absorption.
- Coating: Apply the cyanotype sensitiser solution evenly with a soft brush or sponge. For textiles, some people use a foam roller for smoother coverage.
- Exposure: Place your objects or negatives on the coated fabric and expose to sunlight or UV light. Exposure times are often longer than with paper because fabric absorbs more sensitiser.
- Washing out: Rinse thoroughly in water until the water runs clear.
Toning Cyanotypes on Fabric
The toning process works essentially the same as with paper — bleaching then tannin-rich toning — but fabric changes the feel:
- Bleaching: Use a very diluted washing soda bath (start with half the strength you’d use for paper). Fabric fibres can weaken or fray with strong alkalinity.
- Toning: Tea, coffee, and other tannin-rich brews work beautifully on fabric. The colour often penetrates more deeply and can be softer, with more muted transitions.
- Durability: Toned fabric cyanotypes can be washed, but they’re more light-sensitive than paper prints. Gentle hand washing and avoiding long-term sunlight exposure will help them last.
- Texture effect: The weave of the fabric adds a subtle texture to the image, which often gives toned textiles a lovely, vintage feel.
Example Project:
- Print a cyanotype on cotton tote bags, then tone with strong black tea for a warm sepia look.
- Or try pomegranate-skin toning on silk scarves for deep purples.
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Rachel Bakewell 