Verkkofaint positives on pregnancy tests appear within the reading window and are lightly colored, often indicating early pregnancy. Evaporation lines show up later and are colorless, just test artifacts. If unsure, retest in a few days using. Here's what each signifies on a pregnancy test, and how to tell the difference. Verkkowhat does the evaporation line on a pregnancy test indicate? An evaporation line mimics a positive pregnancy test. A second line shows up when in fact you are.