Brown wash out hair dye?

I have light brown hair and I'm thinking of temporarily dying it a medium / chestnut color. When hair dye starts to fade does it cause bad roots? My color isn't going to be drastically different but I hate the look of hair with uneven hair colors, will that happen as I wash it out? Also, whats a good type to buy for temporary, like what length of time

thanks!

Brown wash out hair dye?

Natural Instincts by Clairol.

This is a temporary rinse that gradually fades over the course of 6-8 weeks. A temporary rinse will fade evenly from root to tip.