007 - Microform (R)
MARC 21 Bibliographic - Full
October 2009
Indicators and Subfield Codes
Field has no indicators or subfield codes; the data elements
are positionally defined.
Character Positions
00 - Category of material
h - Microform
01 - Specific material designation
a - Aperture card
b - Microfilm cartridge
c - Microfilm cassette
d - Microfilm reel
e - Microfiche
f - Microfiche cassette
g - Microopaque
h - Microfilm slip
j - Microfilm roll
u - Unspecified
z - Other
| - No attempt to code
02 - Undefined
# - Undefined
03 - Positive/negative aspect
a - Positive
b - Negative
m - Mixed polarity
u - Unknown
| - No attempt to code
04 - Dimensions
Microfilm
a - 8 mm.
d - 16 mm.
f - 35 mm.
g - 70 mm.
h - 105 mm.
Microfiche, Microopaque, etc.
l - 3x5 in. or 8x13 cm.
m - 4x6 in. or 11x15 cm.
o - 6x9 in. or 16x23 cm.
Aperture Card
p - 3 1/4 x 7 3/8 in. or 9x19 cm.
Other
u - Unknown
z - Other
| - No attempt to code
|
05 - Reduction ratio range
a - Low reduction ratio
b - Normal reduction
c - High reduction
d - Very high reduction
e - Ultra high reduction
u - Unknown
v - Reduction rate varies
| - No attempt to code
06-08 - Reduction ratio
09 - Color
b - Black-and-white
c - Multicolored
m - Mixed
u - Unknown
z - Other
| - No attempt to code
10 - Emulsion on film
a - Silver halide
b - Diazo
c - Vesicular
m - Mixed emulsion
n - Not applicable
u - Unknown
z - Other
| - No attempt to code
11 - Generation
a - First generation (master)
b - Printing master
c - Service copy
m - Mixed generation
u - Unknown
| - No attempt to code
12 - Base of film
a - Safety base, undetermined
c - Safety base, acetate undetermined
d - Safety base, diacetate
i - Nitrate base
m - Mixed base (nitrate and safety)
n - Not applicable
p - Safety base, polyester
r - Safety base, mixed
t - Safety base, triacetate
u - Unknown
z - Other
| - No attempt to code |
FIELD DEFINITION AND SCOPE
When field 007/00 contains code h, it contains special coded
information about the physical characteristics of microform
material.
GUIDELINES FOR APPLYING CONTENT DESIGNATORS
■ CHARACTER POSITIONS
00 - Category of material
h - Microform
One-character alphabetic code that indicates the category
of material to which the item belongs is
microform. Microform is a generic term
for any medium, transparent or opaque, bearing
microimages. A microimage is a unit (e.g., a
page) of textual, graphic, or computer-generated material
that is contained on aperture cards, microfiche,
microfilm, microopaques, or other microformats and that
is too small to be read without magnification. Microforms
may be reproductions of existing textual or graphic
materials or they may be original publications. A fill
character (|) is not allowed in this position.
01 - Specific material designation
Special class of microform to which the item belongs.
(e.g., a microopaque).
a - Aperture card
Card with one or more rectangular opening(s), or
aperture(s), specifically prepared for the mounting or
insertion of a piece of photographic film containing one
or more microimage(s). The cards are usually EAM
(Electrical Accounting Machine) punched cards, commonly
known as IBM cards, that are standardized for use in
card-handling machines. Such cards contain only one
aperture and most frequently have only one microimage.
b - Microfilm cartridge
Consists of a strip of photographic film wound onto a
single core (or hub), housed in a protective container.
Microfilm cartridges require reading equipment (readers
and reader-printers) that is specifically adapted for
their use. Normally, the end of the film is left free for
threading into such equipment. Common film lengths,
widths, and reduction ratios are the same as those of
microfilm reels.
c - Microfilm cassette
Analogous to the sound tape cassette. Consists of a strip
of photographic film wound onto a double core, housed in
a protective container. Microfilm cassettes require
reading equipment (readers and reader-printers) that is
specifically adapted for their use. Because they are
double-cored, they are not threaded when used in such
readers and reader-printers. Usual film lengths are 100
ft (approximately 30 m.) or less. Common film width is 16
mm. and usual reduction ratios are those of microfilm
reels and cartridges.
d - Microfilm reel
Consists of a strip of photographic film wound onto an
unenclosed flanged holder (or reel). Microfilm reels
require manual threading when used in readers and
reader-printers and require equipment that is adapted for
their use. Film lengths are usually 100 ft.
(approximately 30 m.) or less. For microimages produced
by filming textual and graphic materials, the most common
film widths are 35 mm. and 16 mm. and reduction ratios
commonly range from about 10:1 to about 20:1. Sixteen
millimeter film with effective ratios of either 24:1 or
48:1 is most often used for COM
(Computer-Output-Microfilm) microimages.
e - Microfiche
Transparent sheet of photographic film containing
microimages arranged in a grid pattern (a two-dimensional
array) and having a heading that contains identifying
information in text that is large enough to be read
without magnification. Grid patterns vary with reduction
ratios.
Microfiches are grouped in five ranges of reduction
ratios: low reduction (ratios up to and including 15:1),
normal reduction (ratios greater than 15:1 up to and
including 30:1), high reduction (ratios greater than 30:1
up to and including 60:1), very high reduction (ratios
greater than 60:1 up to and including 90:1) and ultrahigh
reduction (ratios greater than 90:1).
The most common microfiche are made by filming textual or
graphic material at a reduction ratio of approximately
24:1. Such microfiche are 105 mm. high and 148 mm. wide
(approximately 4x6 in.) and have a grid pattern that
accommodates 98 microimages made from documents that are
no more than 11 in. high and 8 1/2 in. wide. The heading
area is the width of one row and is found directly above
the first row of microimages.
The most common COM (Computer-Output-Microfilm)
microfiche are made by recording computer-generated data
at an effective reduction ratio of 48:1 on a 105 mm. x
148 mm. sheet of film. Such microfiche have a grid
pattern of 15 rows and 18 columns, comprising 270
microimages. The heading area is the width of one row and
is found directly above the first row of microimages.
Microfiche made at ultrahigh ratios are commonly called
ultrafiche. Ratios and grid patterns have not been
standardized for these microfiche and differ according to
application and method for production.
f - Microfiche cassette
g - Microopaque
Sheet of opaque material bearing a number of microimages
arranged in a two-dimensional array. Microopaques
resemble microfiche. Common dimensions are 3x5 in. and
6x9 in. Common reduction ratios are approximately 24:1 or
20:1. Microopaques usually have identifying information
in text that is large enough to read without
magnification.
h - Microfilm slip
A short strip of microfilm cut from a roll.
j - Microfilm roll
A wound length of microfilm not on a reel, cartridge,
etc.
u - Unspecified
Special material designation for the microform is not
specified.
z - Other
None of the other codes is appropriate. Some microform
types that use code z include:
- microchip - A sheet
of photographic film of very small dimensions,
- microdot - A
minuscule piece of photgraphic film with ultrahigh
reduction ration,
- microform scroll -
A roll of unusually wide photographic film.
Includes microforms such as microchips, microdots, and
microform scrolls.
| - No attempt to code
02 - Undefined
Contains blank (#) or a fill character (|).
03 - Positive/negative aspect
Positive/negative polarity of the microform.
This characteristic is also referred to as the polarity.
a - Positive
Lines and characters appear dark against a light
background.
Microopaques are always recorded as code a.
b - Negative
Lines and characters appear light against a dark
background.
m - Mixed polarity
Mixture of positive and negative images.
u - Unknown
Polarity of the microform is not known. (Some colored
negatives may appear to be positive if the colors of the
original are not known.)
| - No attempt to code
04 - Dimensions
Dimensions of the microform; does not indicate the
dimensions of the image.
For example, 16 mm. images on 35 mm. microfilm are coded f
(35 mm.). Only the most common dimensions are indicated.
Only codes that exactly match the measurement of the item
as given in the physical description should be used. If no
code exactly matches, code z is used.
The width of a microfilm is indicated in millimeters.
The height and width of a microfiche, microopaque, etc. are
indicated in inches or centimeters. The first dimension is
the height, the second is the width. The standard
microfiche (105 mm. x 148 mm.) is coded m.
a - 8 mm.
d - 16 mm.
f - 35 mm.
g - 70 mm.
h - 105 mm.
l - 3x5 in. or 8x13 cm.
m - 4x6 in. or 11x15 cm.
o - 6x9 in. or 16x23 cm.
p - 3 1/4 x 7 3/8 in. or 9x19 cm.
Height and width of an aperture card in inches or
centimeters.
u - Unknown
Dimensions are not known.
z - Other
None of the other codes is appropriate.
| - No attempt to code
05 - Reduction ratio range
Reduction ratio range for a microform. The specific
reduction ratio is recorded in 007/06-08 (Reduction ratio).
For microfilm created by other than COM
(Computer-Output-Microfilm) processes and for microopaque
microprints, codes a and b are most likely to be used. For
COM microfiche or microfilm, the reduction ratio is
actually an expansion ratio and refers to the ratio of
expansion required to produce a legible image. Most COM is
created at 024-048 reduction ratios (codes b and c), though
some COM fiche is at higher ratios (e.g., 072). Codes b-e
are used with other types of microforms (e.g., microfiche,
ultrafiche, etc.). The most commonly encountered microfiche
are normal reduction (code b).
The reduction ratio is usually given on the microform
itself. If it is not present, one must know the dimensions
of the original item and the size of the image on the
microform in order to code the information needed in
007/05.
a - Low reduction ratio
Less than 16:1 ratio (less than 016).
b - Normal reduction
Between 16:1 and 30:1 (016-030).
c - High reduction
Between 31:1 and 60:1 (031-060).
d - Very high reduction
Between 61:1 and 90:1 (061-090).
e - Ultra high reduction
Over 90:1 (over 090).
u - Unknown
Reduction ratio is not known.
v - Reduction rate varies
Not all parts of the microform have the same reduction
ratio (e.g., the contents of two books may be microfilmed
onto one piece of film; the type face on the books may
differ, so that one of the books may be filmed at a 14:1
ratio and the other at a 18:1 ratio).
| - No attempt to code
06-08 - Reduction ratio
Number specifying the reduction ratio for a microform,
recorded as three digits. The number is right justified and
each unused position contains a zero (e.g., 015, 048). A
hyphen is used for any unknown portion of the reduction
ratio (e.g., 03-, 1--, or ---).
A code indicating the reduction ratio range is
recorded in 007/05. Generally, the specific reduction ratio
is recorded when it is ultra high (code e in 007/05). If
the ratio is not ultra high, recording the specific ratio
is less essential. Three fill character (|||) are used when
no attempt has been made to code this data element.
09 - Color
Color of the image for microforms.
b - Black-and-white
Image is in black-and-white (usually
black-and-transparent).
Includes only one color or hue other than black, for
example, blue-and-white (blue-and-transparent). Always
used for microopaques.
c - Multicolored
Has more than one color.
m - Mixed
Combination of one-color and multicolored images.
u - Unknown
Color of the microform is not known.
z - Other
None of the other codes is appropriate.
| - No attempt to code
10 - Emulsion on film
Type of light-sensitive material on the film.
Proper storage and use of microforms requires
identification of the emulsion they contain.
a - Silver halide
Emulsion is a compound of silver and halogens. Silver
halide microforms always appear black-and-white
(black-and-transparent).
b - Diazo
Emulsion consists of sensitized layers composed of
diazonium salts that react with couplers to form dye
images. The color of the image is determined by the
composition of the diazonium compound as well as the
couplers used in the process and may be black, violet, or
another color.
c - Vesicular
Light-sensitive component is suspended in a plastic
layer. On exposure, the component creates optical
vesicules (bubbles) in the layers. These bubbles form the
latent image. The latent image becomes visible and fixed
by heating the plastic layer and then allowing it to
cool. Vesicular films are commonly blue or beige in
color. They do not appear to have much contrast (very
high density) until projected in a microform reader.
m - Mixed emulsion
For example, a microfilm may have slices of film with one
type of emulsion and other slices with another type of
emulsion.
n - Not applicable
Item does not have emulsion on film.
Used for microopaques.
u - Unknown
Emulsion on the film is not known.
z - Other
None of the other codes is appropriate.
| - No attempt to code
11 - Generation
Generation aspect of a microform.
a - First generation (master)
Camera master or COM recorder master.
Used for all master films that are made on archival stock
in accordance with archival productions standards and
that are given archival storage under relevant ISO
standards.
b - Printing master
Any generation employed mainly for the production of
other microforms.
Used for all masters that are not manufactured, produced,
and stored in accordance with archival standards.
c - Service copy
Microform made from another microform that is intended
primarily for use rather than for production of other
microforms. Always used for microopaques.
m - Mixed generation
Made up of a combination of generations of film.
u - Unknown
Generation aspect is not known.
| - No attempt to code
12 - Base of film
Base of the film.
Safety base film is a comparatively nonflammable film base
that meets the standard requirements for a safety base. On
some film, the phrase safety base or a small
equilateral triangle appears on the edge of microforms.
Some microfilm produced overseas has similar notations in
foreign languages. Vesicular and diazo microforms are
always a safety base, as are silver halide microforms
manufactured in the United States since approximately 1951.
Nitrate film base is a highly flammable film base that does
not meet the requirements for safety base film.
a - Safety base, undetermined
Type has not been identified.
c - Safety base, acetate undetermined
Acetate safety base film whose exact type cannot be
determined, i.e., where it is unknown if the type is
diacetate or triacetate.
d - Safety base, diacetate
Cellulose diacetate film base. Introduced before World
War I for home movies, diacetate base was more expensive
and unpredictable than nitrate base and so failed to gain
acceptance in professional 35 mm. film production.
Diacetate film base was at times used for microfilming of
documents.
i - Nitrate base
Cellulose nitrate film. Cellulose nitrate support or base
was used in the manufacture of 35 mm. film (and some 17.5
mm. film) until 1951. Nitrate base film is no longer
manufactured. Nitrate film base was at times used for
microfilming of documents.
m - Mixed base (nitrate and safety)
Combination of nitrate base and safety base film. The use
of mixed bases, spliced together, can be found in
microforms from the early 1950s.
n - Not applicable
Microform on a reflective rather than a transparent base.
Microopaques (which can be termed microcard or
microprint) are an example of a microform not produced on
a film base and are coded n.
p - Safety base, polyester
Film base is made of a synthetic resin (e.g., estar).
During the 1980s, it became the most widely used base for
microfilming of source documents.
r - Safety base, mixed
Mixed safety base films are spliced together; no nitrate
film.
t - Safety base, triacetate
Cellulose triacetate film base. Cellulose triacetate is a
high acetal compound with very low flammability and slow
burning characteristics. From 1951, triacetate has been
used for professional as well as for amateur produced
moving image film. It has also been used at times for
microfilming of documents.
u - Unknown
Base of film of the microform is not known.
z - Other
Bone of the other codes is appropriate.
| - No attempt to code
■EXAMPLES
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007 |
hd#bgc---cuuu
[Item is a microform (007/00); released as a
microfilm reel (01); it has negative polarity (03); is 70
mm. (04); has a high reduction ratio (05); and is in
color (09). Its emulsion (10), generation (11), and film
base (12) are unknown.] |
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007 |
he#bmb024baca
[Item is a microform (007/00) (originally a printed
work that has been filmed for reproduction in the
microfiche format); released as a microfiche (01); has
negative polarity (03); is approximately 4x6 in. (04);
has a normal reduction ratio (05) of 24:1 (06-08); is
monochromatic (09); has an emulsion of silver halide
(10); is a service copy (11); and is on safety base film
(12).] |
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007 |
hd#afa014bcaa
[Item is a microform (007/00) (a newspaper, filmed
for reproduction); released as a microfilm reel (01); has
positive polarity (03); is 35 mm. (04); has a low
reduction ratio (05) of 14:1 (bytes 6-8); is
monochromatic (09); has vesicular emulsion (10); is a
service copy (11); and is on safety base film
(12).] |
INPUT CONVENTIONS
Field length - Field 007 for the category of
material microform currently has thirteen
character positions defined for it.
CONTENT DESIGNATOR HISTORY
007/01 - Specific material
designation
h - Microfilm slip [NEW,
2009]
j - Microfilm roll [NEW, 2009]
007/02 - Original versus reproduction aspect [OBSOLETE,
1997] [USMARC only]
Defined codes were: f (Facsimile), o (Original), r
(Reproduction), and u (Unknown).
007/12 - Base of film
b - Not safety base [OBSOLETE, 1991]
Code b was made obsolete when 007/12 for microforms was
made consistent with the 007/12 (Base of film) for motion
pictures and code i (Nitrate base) was defined.