This is probably due to the perennial difficulty of making good blue dyes and pigments.

Since the 18th century, natural blue dyes have largely been replaced by synthetic dyes.

The blue dyes came up with it.

Sometimes it is mixed with blue dyes to color processed products green.

His skin, burnt a deep mocha, was tattooed with blue and crimson dyes.

The most commonly used pigments are blue and violet dyes.

"I thought that made only blue dyes."

Usnea species have been used to create orange, yellow, green, blue and purple dyes for textiles.

Yellow and blue dyes in colored paper bleed into a stamps too.

Many blue dyes have this structure as their basic shape.