I'm currently researching ways to get the human perceived colors red, green and blue when you only have a mostly blue spectrum available at your source (using electroluminescence). The solution should be quite simple so that an engineer can build this without needing a laboratory.
Simple color filters filter every frequency but one frequency range, so the light gets darker. So this is not very feasible to use this.
However then I found this quote on wikipedia:
high luminance inorganic blue phosphor is used in combination with special color conversion materials
So there seem to exist materials which red shift blue light by passing the light though (?) these materials. Do such materials exist?
According to this answer (Is it possible for a material to shift the frequency of all light reflected off of it by a specific and constant value) only one technique was named (Raman scattering) which is again not practical feasible to use.