藍 - indigo

dyer's knotweed (Persicaria tinctoria, used to produce indigo dye)

dark indigo

deep indigo

indigo

indigo

little spinefoot (Siganus spinus); black spinefoot; black trevally; blue-spotted trevally; spiny rabbitfish

indigo

blue-green bacterium; cyanobacteria; cyanobacterium

Mercurialis leiocarpa (species of mercury whose leaves can be used to produce an indigo dye)

indigo-dyed leather

stencil dyeing produced with various shades of indigo

cabbage