I think washing detergent for white fabric can contain bleach, so the clothes will stay white and won’t become grey. If this is the case, it’ll gradually fade any colors of colored fabric.
And the other way around it won’t keep the white perfectly white.
Dunno about the bleach part, that might be in some as well, but typically white fabric detergent contains optical brightener that counters the typical yellow tint of worn garments by emitting extra blue light (and your eyes perceive the full presence of the spectrum as white). That’s also why this whitening effect will fade off if you then use detergent that doesn’t contain brighteners: you are washing out those blue light particles once again.
I think washing detergent for white fabric can contain bleach, so the clothes will stay white and won’t become grey. If this is the case, it’ll gradually fade any colors of colored fabric.
And the other way around it won’t keep the white perfectly white.
Dunno about the bleach part, that might be in some as well, but typically white fabric detergent contains optical brightener that counters the typical yellow tint of worn garments by emitting extra blue light (and your eyes perceive the full presence of the spectrum as white). That’s also why this whitening effect will fade off if you then use detergent that doesn’t contain brighteners: you are washing out those blue light particles once again.
https://en.wikipedia.org/wiki/Optical_brightener