1) Pricking punctures 2) Tiny openings 
Tiny holes in the emulsion of negatives or printing plates.
Tiny holes in the emulsion of a photographic negative that must be opaqued before plate making. 
Small holes occurring as imperfections that penetrate entirely through a layer of material. 
Small holes in through a dry film which form during application and drying of paint.
See moons.
Small holes in a finish.
A coating defect consisting of the randomly spaced small round holes (as a straight pin would make in the cured film, which quite often occur in large numbers. The open area (pinhole) usually exposes bare substrate. Contaminated substrate or improperly dispersed lubricant or additive may cause pinholes. Pinholes are typically caused by laminations,...Microscopic imperfection of the coatings, that is, microscopic bare spots, also microscopic holes penetrating through a layer or thickness of light gage metal.
Microscopic imperfection of the coatings, that is, microscopic bare spots, also microscopic holes penetrating through a layer or thickness of light gage metal.