Ultraviolet Light: Used to describe rays of light that cannot be seen and that are slightly shorter than the rays of violet light. Measured in nanometers UV light falls in the 360-440 nanometer range. This invisible light range is the light needed to expose emulsions.
Underbase: A thin coating of ink printed first and cured to act as a base for which all other colors are to be printed on. Underbasing is usually required when printing multi-color designs on colored shirts.
Undercure: A print in which the ink did not cure completely.
Undercutting: Unwanted screen stencil exposure around the edges of an image caused by light scattering and over exposure.
Underexposed: When insufficient screen exposure time is used resulting in a soft stencil that can break down during print production.
UV Inks: Types of inks that when exposed to UV light will harden or cure.