Most Of Us,

have a favourite colour, mine is blue,

which is what this book is all about, all images © Isabelle Simler, French illustrator and author Isabelle Simler looks at the Earth’s rarest colour. The Blue Hour winds through the natural world on a journey to spot the pigment, from a bluejay resting on ice-coated branches to robin’s eggs to midnight skies and ocean depths. Simler focuses on “this time of day, when daytime animals enjoy the last moments before nighttime animals wake up. This in-between where the sounds and smells are denser and where the bluish light gives depth to the landscapes.”

because the pigment isn’t naturally occurring—plants, insects, and animals that appear blue are simply reflecting that portion of the spectrum rather than emitting it—the illustrations spotlight the uncommon specimens that populate the world with indigo, turquoise, and azure, The Blue Hour is available on Bookshop along with a few of Simler’s other illustrated titles. Currently, she’s working on Topsy Turvy, a book that focuses on mimetic insects, which you can follow on her site and Instagram, I wonder if books will be made in other primary colours as their theme?