In Celebration of The Cyanotype!
Cyanotype: The Original Colour-Changing Print
If you’ve ever held a cyanotype print in your hands, its paper washed in deep Prussian blue, with objects rendered in ghostly white, you’ll know it feels like magic. Long before digital filters and colour photography, this process gave us one of the earliest colour-changing effects, where sunlight itself transformed chemistry into art.
This month, artists and photographers across the globe come together for World Cyanotype Day, observed annually on the last Saturday of September, in 2025 that falls on September 27th.
What Is Cyanotype?
Cyanotype is an early photographic process invented in 1842 by scientist Sir John Herschel, by brushing paper (or fabric) with a mix of iron salts, then exposing it to sunlight, images appear in striking shades of blue.
Before exposure: the surface looks pale greenish,
During exposure: UV light triggers a chemical reaction,
After washing in water: the image is “fixed” in a deep, permanent blue,
This vivid pigment is called Prussian blue, and one of the first to use cyanotype creatively was Anna Atkins, who in 1843 documented algae and ferns using cyanotypes, creating what many consider the first book of photographs ever published.
Why It’s an Early “Colour-Changing” Product
What made cyanotype so revolutionary?
Transformation: paper literally changed colour under light,
Accessibility: no darkroom needed, just sunlight and water,
Longevity: cyanotypes can last for centuries with proper care,
To Victorians this was more than photography, it was proof that light could change matter, and in modern terms it became the first “colour-changing product” we could hold in our hands.
How to Make Your Own Cyanotype Print
You don’t need a lab, just a sunny afternoon.
You’ll need:
Pre-sensitised cyanotype paper (available in art shops or online),
Flat objects (leaves, lace, feathers, keys, negatives),
A piece of glass (optional, to hold objects in place),
A tray of water,
Steps:
Place your object on the paper in bright sunlight,
Wait 5–15 minutes as the paper darkens,
Rinse the paper in water until unexposed areas turn pure white,
Leave to dry, your Prussian blue artwork will deepen as it cures,
Tip: try toning with tea or coffee for sepia-brown effects,
Why World Cyanotype Day Matters
World Cyanotype Day isn’t just for photographers, it’s a reminder of:
Our heritage: linking back to Herschel’s science and Atkins’ artistry,
Hands-on creativity: in an age of screens, cyanotype invites us to slow down,
Global connection: artists everywhere share their cyanotypes online, creating a worldwide gallery in blue,
Final Thoughts
From algae pressed by Anna Atkins to modern street murals, cyanotype has travelled nearly two centuries, still fascinating, still transforming, still changing colour before our eyes.
So this September, celebrate World Cyanotype Day (September 27, 2025) by making your own sun-prints, watch the pale green turn to deep blue, and remember that every cyanotype isn’t just an image, it’s a piece of alchemy.