How squid change color?

-I didn't know squids use Facebook. Why is this question here?Squid and other marine creatures create light by mixing two substances into a third that gives off light, similar to the mechanism by which a common firefly lights up or the way the popular plastic green glow-sticks work. To get a glow-stick to "glow," it is bent. This causes the two chemicals inside to mix and react, yielding a third substance that gives off light. A new molecule forms when the reaction is complete, and in the ocean it typically glows blue to green in color. In some organisms the photophores are simple glandular cups. In others they are elaborate devices with lenses for focusing, a color filter, or an adjustable flap that serves as an off/on switch.
Squid is chromatophore. Surface skin cells able to be manipulated to pass different wavlengths of light to reflect.
these creatures have special pigment cells called chromatophores in their skin. By controlling the size of the cells they can vary their color and even create changing patterns.
do they not only release a black colored toxin? i don't know i just wanted to say i really like your hair!