Evap Line Question:

I know tests are invalid after 10 minutes, not questioning that. But I've heard pink dye evap lines are colorless. So if you took a test and look at it after its evaporated , and it's pink, does that mean you may be pregnant ? Or can pink dye tests evap with color too?...I know blue dye tests do evap with color sometimes but I don't know about pink, anyone have an experience with this ?