please explain an evaporation line.. I've taken four tests the first three have been extremely faint (stands on head bend over backwards finally sees line lol) but the last test I took at 11dpo was faint until about an hour after I took it. It got fairly dark & I did the evaporation test (dry out the test then use drops of water to rid the test of any unneeded dye) test was still positive. Please help me figure this out.