A cyanotype sun print turns leaves and flowers into crisp white silhouettes on deep Prussian blue. The sun does the work. You coat fabric or paper with a light-sensitive solution, lay your plants on top, set it in sunlight and rinse it in water. Justine Silva shows the method on large cotton gauze panels printed with palm fronds and trailing vines.
How to make a cyanotype sun print: the short version
- Pick a natural fabric or a heavy paper.
- Mix cyanotype part A and part B in dim light and coat the fabric.
- Dry it in the dark and keep it covered until you print.
- Lay leaves flat under glass or plexiglass and expose in sun for 10 to 20 minutes.
- Rinse in cold water until the water runs clear, then hang to dry.
Fabric or paper?
Natural fibres hold the solution evenly: cotton, linen, silk or rayon. Synthetics take it in patches. Wash new fabric first to remove sizing. For paper, use watercolor paper or heavy drawing paper that will not fall apart in the rinse. If you want to skip mixing chemicals, pre-coated sun print paper works for kids and small pieces.
Working in the dark
Once part A and part B are mixed, the solution reacts to UV light. Coat and dry your fabric in a dim room. Justine works in a bathroom at night with a string of warm copper lights, which give enough light to see without exposing the fabric. Store coated pieces in a sealed box or a black bag until you print.
How long to expose
Bright midday sun takes about 10 to 20 minutes. Cloudy days can take an hour or more. The coated fabric starts yellow green, turns blue green, then a dusty grey blue when it is done. The print always looks paler before rinsing. Flat, solid objects give the sharpest edges. Lacy ferns and thin petals give soft, see-through shapes.
Choosing plants
Palm fronds, ferns, ivy, Queen Anne's lace and grasses all print well. Pick them the day you print so they are still supple, or press them flat a few days ahead. Thick stems hold the glass up, so trim them or set them at the edge.
Why hydrogen peroxide?
A splash of 3 percent peroxide in the rinse water oxidises the print, so it reaches its full deep blue right away instead of over a day or two. It is optional. Plain cold water works too. The colour develops more slowly.
Ideas and care
Print tea towels, pillow covers, tote bags, wall hangings or a set of cards. Kids love collecting leaves for this. Wash finished fabric by hand in cold water with a phosphate-free soap. Detergents with phosphates or bleach can fade the blue to yellow.
Common problems
- Blurry edges. The leaves lifted. Weigh them down with glass and tape.
- Pale print. Too short an exposure, or the coating was too thin.
- Blue all over, no image. The fabric saw light before printing. Keep it boxed until the last second.
More fabric printing ideas: try block printing on fabric, ice dyeing or a tie-dye shirt. Collect your plants ahead of time with how to press flowers so they lie flat.
