Blue can have different wavelengths for additive color mixing. This is related to the requirement for the largest possible color space for additive color mixing of red, green, blue( RGB) and to the requirement that the third primary color cannot be created from two primary colors. These requirements are fulfilled by several wavelengths, but are always to be seen in connection with the other two primary colors. Blue has an international wavelength of 436 nm.
The various color models define the color blue in the CIE color space slightly differently from each other. For example, the EBU has defined the xy coordinates for blue as 0.155/0.07, whereas in NTSC the coordinates are 0.14/0.08. In standard RGB( sRGB), blue is specified in the CIE color space with the coordinates 0.1500/0.0600.