Pinholing - What is pinholing?

Answer:

In printing, pinholing is a defect in the print characterised by the appearance of small holes in an area of solid print due to the failure of a printing ink to form a complete film before it dries. Pinholing occurs when there isn't enough ink to form a complete film over the entirety of the intended print area or when the ink doesn't spread evenly across the substrate, which is usually caused by low ink viscosity or by the ink drying too quickly, meaning it dries before a full film can form.