Strike-through
Strike-through turns up in 2 fields: paper optics, nonwovens. Here is what it means to the people in each one.
Strike-through in paper optics
Penetration of ink or its oil vehicle through a sheet far enough to darken or stain the reverse side.
Liquid ink, or the oil carrying it, travels down through the pore network until it darkens the sheet from inside or reaches the back surface. Open, absorbent sheets with little sizing or low density suffer most, as do lightweight grades printed with heavy coverage. It is controlled with sizing, filler, surface treatment and ink formulation, and it adds to show-through because wetted fibers stop scattering light.
"That's not just show-through, it's strike-through: you can see the oil stain on the back under the loupe."
Strike-through in nonwovens
Hygiene test time for a set dose of liquid to pass through a topsheet into the absorbent pad underneath.
A measured gush of synthetic urine is released onto a topsheet lying on a stack of standard filter paper, and electrodes time how long the liquid takes to get through, usually a few seconds or less. Repeat insults on the same spot show whether the hydrophilic finish washes off. Fast, stable strike-through with low rewet is the main liquid-handling target for diaper and pad topsheets.
"First strike-through is 2.1 seconds but the third insult is 6, so the finish is washing out."