Yes, demi permanent hair color can be applied over any type of color. It will refresh the original color very nicely.
Yes you can.
yes you can will it kill your hair yes but you can
Splat hair color is not a permanent color it is a semi permanent color over bleached out hair, once the melanin (color) is removed from the hair the hair is very porous meaning it absorbs like a sponge and the cuticle of the hair is open so once you have put a semi permanent over it which just deposits that cuticle is still open leading to the color fading out!
apply all over
If the scalp is in good condition and was not irritated by the semi permanent color, it's OK to apply permanent color within 24 hours after initial color service.
Depending on the type of hair color in your hair, it will either wash out over time, fade or grow off your hair. If you have temporary hair color on your hair it will wash out in 2 to 3 shampoos. If you have a semi-permanent hair color it will fade off in 4 to 6 weeks or less. If you have a permanent hair color on your hair it will have to grow off.
yes, but semi-permanent colors will not lift you natural hair color, and if it you put a lighter color over a darker color it will not do much other than give shine
Do you mean pastel hair dye? It depends on if you use a permanent dye or a semi-permanent. Semi-permanent hair dyes will wash out and fade over time; permanent hair dyes will stay in the hair until you cut it or dye it another color.
Yes, it's fine to apply permanent color over semi permanent.
It is recommended that you wait 4-8 weeks between color treatments because the chemicals can damage your hair and you need to give your hair time to restore itself. You can apply the semi permanent hair color a couple weeks later, but make sure to condition your hair well and check with your stylist before taking that risk.
You don't. over time it will fade after so many washes. If you want to get rid of the color you'll have to dye it your natural color