Can we talk about evap and faint lines for a minute?

Ok so I understand that tests need to be read in the correct time frame. Does reading it a minutes or two later actually make a line appear where there was not one? Or will it simply make an existing line darker?

Background: I’m 12dpo. Tested with a Pregmate hpt strip this morning. Every month I stare and stare and can never see even a very faint line. I refuse to trick myself. This morning around 4 min (says to wait 5 and read), I saw a very faint line. Hubby did too. By 5 min it was still very faint but maybe a teeny bit darker. With one like 6 or 7 it was clearly positive ( I know past the reading window).... didn’t take a picture at the time, was too excited, confused, worried, happy, emotional at the time. I plan to test again tomorrow or the next day but want to be excited today. Does evap more so make lines that are there simply darker? Or is there a chance we both imagined it and now the evap line appeared from our imaginary line?