Serigraphy / Screen Print
Sure shirts all have got a black serigraphy / screen printing (Wikipedia) on front and back (usually only on the top of the back). The screen prints are of good quality, barely palpable and wash resistant. The black color is printed into white or colored wrinkle fabric.
What is Screen Printing / Serigraphy?
In short screen printing can be described as follows:
Screen printing is a printing technique in which the ink is printed / pressed through a fine-meshed fabric with a rubber squeegee, right onto the fabric. The mesh has to be prepared with a blocking stencil, an opaque film according to the desired image. By moving the squeegee across the mesh, ink is filling the open apertures of the mesh with color, while the impermeable areas are left out.