Hardener- Curing agent; catalyst.

Hardboard- Reconstituted natural wood that is fabricated by reducing natural wood to fibres and then pressing the fibres together into panels of various thicknesses.

Hiding Power- The ability of a coating to obliterate the surface below it.

Hold-Out- The ability of a paint film to dry to its normal finish on a somewhat absorptive surface.

Holidays- Voids in the dried paint film.

Honeycombing- Lack of vertical film integrity; voids.

Hot Spots- Incompletely cured lime spots that bleed through the coating on a plastered wall.