Silk screen is to print the "Text" on the PCB board, usually the color of the silk screen is white, with Gold Phoenix we also provide black silk screen. Screen printing is a printing forms open areas of mesh that transfer ink or other printable materials which can be pressed through the mesh as a sharp-edged image onto a substrate. A roller or squeegee is moved across the screen stencil, forcing or pumping ink past the threads of the woven mesh in the open areas.
For the PCB designer what you really need care is the color of the silk screen, you need one side silk screen or two side silk screen. With Gold Phoenix we offer white silk screen and one side silk (top side or bottom side) silk by default. Two side silk screen( print text on both top and bottom side) will result extra charge.
Another thing you maybe should know is the min size of the silk screen the PCB manufacture can support. With Gold Phoenix the min text size we support is height 25mil, width 6mil. Small text size make it difficult to read, the min text size we suggest is width 6mil, height 50mil.