Carbonless paper is coated with two different types of chemicals:
CF or also known as front coating, and CB or back coating. The
chemicals are held in tiny capsules that are released when the
capsules rupture due to pressure from a pen or printer.
For a three-part carbonless copy paper receipt, it can be divided
into upper paper, middle paper, and lower paper. The upper paper is
also called back-coated paper (codename CB, i.e. Coated Back), and
the back of the paper is coated with microcapsules containing Limin
pigment oil; the middle paper is also called front and back
double-coated paper (codename CFB, i.e. Coated Front and Back), and
the front of the paper is coated with a colorant, and the back is
coated with microcapsules containing Limin pigment oil; the lower
paper is also called front-coated paper (codename CF, i.e. Coated
Front), and the paper surface is only coated with a colorant.
Self-contained paper (codename SC, i.e. Self-contained) is a paper
with a microcapsule layer containing Limin pigment oil on the back,
and a colorant and microcapsules containing Limin pigment oil on
the front.
The upper and lower papers do not have a copying effect, only the
middle paper has a copying effect. When using documents printed on
carbonless paper, they are generally equipped with a small piece of
cardboard to separate the form to prevent excessive writing force
from causing other forms underneath to be copied.
Carbonless paper generally comes in four colors: white, red, blue,
and green, which serve to distinguish between the copies.
