What is the difference between blue dye line and pink dye line on a pregnancy test , i keep getting really fainted positive with the blue and not pink?

Evaporation lines can appear on pregnancy tests that use a blue indicator and be mistaken for a positive test. These evaporation lines are generally faint, grey in color, and appear after 10 minutes. A true positive will be blue and appear within 5 minutes. A faint positive test very early in the pregnancy should be repeated in two days and will be much darker if you are indeed pregnant.