What colour are evaporation lines?

[pinkroseblush]

Are they always grey, or can they be the colour of the line that would come up if pregnant? I am getting a line an hour or so after the test and it is blue but very faint. Is that proper line or evaporation line?

if the line appears after 10 mins it is evap

I think it is not a proper line.
The text instructions will have a time limit (usually 10 mins) after which you shouldn't read the test because eveporation lines do develop after that time.

Of course, just because you've had a negative this time does not mean you are not pregnant; you might just be testing a bit too early, so try again in a couple of days maybe.