Modern technology: Serigraphy
Serigraphy, also known as silkscreen printing, is a method that utilizes a screen of silk or other fabric, a squeegee, paint, and a substance, such as glue, that is non-permeable.
The artist applies the non-permeable substance to the fabric where she does not want paint to seep through (like creating a stencil). Then, paint is applied and pressed throughh the porous areas of the screen (with the squeegee) onto paper or some other surface.
Silkscreen printing is a popular commercial method. Many T-shirts with images have been silkscreened.