MARC21-007: Base of film of microform
mixed base (nitrate and safety)
Combination of nitrate base and safety base film.
m
nitrate base
Cellulose nitrate film.
i
not applicable
A reflective rather than a transparent base.
n
Used for microopaques (which can be termed microcard or microprint).
other
Base of film other than safety base, undetermined, safety base, acetate undetermined, safety base, diacetate, nitrate base, mixed base (nitrate and safety), not applicable, safety base, polyester, safety base, mixed, safety base, triacetate.
z
safety base, acetate undetermined
Acetate safety base film whose exact type cannot be determined.
c
safety base, diacetate
Cellulose diacetate film base.
d
safety base, mixed
Mixed safety base films are spliced together; no nitrate film.
r
safety base, polyester
Film base is made of a synthetic resin (e.g., estar).
p
safety base, triacetate
Cellulose triacetate film base.
t
safety base, undetermined
Type has not been identified.
a
unknown
u
Published