Dear Kenshinlvr,

If you look in either Yann's cel FAQs or Brian's cel FAQs
(both of which are listed in cels.org), a cel that is
painted black on the back means that the cel was filmed with
lighting on the back.  The black paint is used to prevent
the cel from looking transparent when lit this way (as you
can see from the cels that don't have the black paint on
the back when you hold them up against the light).  It makes
the character look opaque.  I hope this helps!


Sincerely,

Sonia