Evap line question

SM • Wife 💑 Child of God 🙌 Dog mom 🐶 2 babies in Heaven 8/2017 & 4/2018 👼👼

How can you tell the difference between a evap line and a faint positive? I took a test earlier and about six minutes after it sat there, but still within the 10 minute window, there was a faint line that had color to it but after 30 minutes or so the coloring had went away but you can still see the line. Is that considered an evap?