Cyanine

noun

1. Any of various blue dyes, used to sensitize photographic emulsions to a greater range of light.
2. In chem., a beautiful blue dye, chinoline blue, prepared by acting on a mixture of chinoline and lepidine with amyl iodide. Unfortunately it does not resist the action of light, and hence has lost its importance as a dyestuff, but, it is used in making orthochromatic plates for photography.
3. The blue coloring matter of certain flowers, as the corn-flower, violet, and species of iris.
4. One of a series of artificial blue or red dyes obtained from quinoline and lepidine and used in calico printing.
5. Any of a family of synthetic blue dyes used in photography etc.