Offset Lithography

Offset litho uses etched aluminium plates wrapped around a cylinder which then transfers ink onto a rubber 'blanket' cylinder and from there onto the paper/plastic/fabric ect.

This process can either be sheet fed or web fed, web being huge rolls of paper used for very large print runs.

This process uses CMYK colour process and has a different part of the machine for each colour separation, therefore an image is printed using four different etched aluminium sheets.