In the ceramic manufacturing process, after the initial tile forming stages and subsequent steps along the glazing line, it is common practice to apply protective glazes or grit as a final layer. These applications can, in some cases, involve significant quantities and thicknesses, which must be carefully managed.

If the process parameters are not properly controlled, this stage can give rise to various issues that may compromise the ceramic surface, both aesthetically and functionally. Among the most frequent defects is the formation of small holes or surface pinholes, which may appear either locally concentrated or evenly spread across the surface. This issue can become evident as early as the application phase and often persists even after firing. It can stem from a variety of causes, not always easy to identify.

So, what are the main factors behind this defect, and what should be considered to effectively address and prevent it?