I think the one on the bottom has the darkest evap line. Did any of these have a hint of anything under the time limit?
I do progressions, and obviously that means all the tests have dried, and I do indeed see a darkening among evap lines--ie much darker evap lines at later DPO than early DPO. So I'm on the "it means something" team, with one important rule I use for myself: I have to see *something* during the time limit to hold onto the test and include it in my progression...