| COMARC/B | September | 2003 |
This field contains coded data relating to microforms. It is repeatable when more than one microform is described in a single bibliographic record.
A code is entered for specific material designation.
| a | aperture card |
| b | microform cartridge |
| c | microfilm cassette |
| d | microfilm reel |
| e | microfiche |
| f | microfiche cassette |
| g | micro opaque |
| h | microfilm slip |
| z | other |
A code indicates dimensions.
| a | 8 mm (microfilm) |
| d | 16 mm (microfilm) |
| f | 35 mm (microfilm) |
| g | 70 mm (microfilm) |
| h | 105 mm (microfilm) |
| l | 3x5 in. (8x13 cm) (microfiche or micro opaque) |
| m | 4x6 in. (11x15 cm) (microfiche or micro opaque) |
| o | 6x9 in. (16x23 cm) (microfiche or micro opaque) |
| p | 3 1/4 x 7 3/8 in. (9x19 cm) (aperture card) |
| u | unknown |
| z | other |
A code indicates a degree of reduction ratio.
| a | low reduction |
| b | normal (16x - 30x) |
| c | high (31x - 60x) |
| d | very high (61x - 90x) |
| e | ultra-high (91x - ) |
| u | unknown |
| z | other |
In the subfield of three-character length the numeric value is entered indicating the magnification needed to make the microform legible. It is normally stated on the item. The value is entered right justified. If single digit is missing, it is replaced by zeroes.
A code indicates the type of emulsion on film.
| a | silver halide |
| b | diazo |
| c | vesicular |
| u | unknown |
| v | mixed emulsion |
| z | other |
A code is entered for the film generation.
| a | first generation (master) |
| b | printing master |
| c | service copy |
| u | unknown |
| v | mixed generations |
130 ⊔⊔ ae bb cm db e024 fa ga hc ia (A monochrome microfiche with negative polarity, 11 x 15 cm big, with normal reduction ratio of 1:24. It is on the silver halide film safety base.) *
130 ⊔⊔ ae ba cm dc fa ga hc (Monochrome microfiches – positives, 11 x 15 cm big, with high reduction, on the silver halide base.)