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.
Also heard as
- bleed-through
Related terms
Show-through
Print on the back of a sheet, or on the page beneath, visible from the front because too much light passes through.
Opacity
A sheet's ability to hide what lies behind it, expressed as a percentage from readings over black and white backings.
Ink holdout
The ability of a paper surface to keep ink and its vehicle on top instead of absorbing them.