Described herein are methods of dyeing fibers, and dyed fibers and textiles made using the methods. The methods involve contacting a fiber with a dye liquor at a dye liquor temperature of about 30° C. to 115° C. to form a dyed fiber, wherein the dye liquor components include at least N,N′；-diacetyl indigo and a salt solution having ionic strength of about 0.03 M (moles/liter) to 1 M and pH of about 3 to 8 at 20° C. The contacting is generally carried out for a contact period of about 10 seconds to 30 minutes, for example by immersing the fiber in the heated dye liquor. By using the disclosed methods, N,N′；-diacetyl indigo is substantially uniformly distributed on the dyed fiber to provide intense, vibrant colors affixed thereto. Dyed textiles display substantially uniform color.
