Microfilming at SVK

Microfilm Workflow:

Microfilm Standards

(i) Choice and Quality of Film –

For high-contrast archives like text, line drawings and engravings Pan-chromatic AHU microfilm on polyester base works good and recently it has been improved and optimized to a large extend.

For high range of gray or continuous tones like books containing photographic reproductions or color material that is to be filmed in black and white, half-tone microfilm such as Kodak 2468 or Kodak 3468 will be best producing film of positive polarity.

For ensuring best possible quality of the master as well as the duplicate, a Quality Index of 8 is suggested.

35mm roll film for the master for digitization is the best, which guarantees sufficient quality even up to larger sizes like 60-80 centimeters.

Along with the quality index, density of the film, resolution and background shadow should at least meet the ISO standard. Distortions should be avoided.

(ii) Film Technique –

Uniform reduction ratio for the complete project as a whole

Uniform positioning of the material, possible optimal position is to place the material in the middle of the front edge.

Contrast between background and filmed material should be carefully controlled.

Alignment of the material should be properly checked for the whole project.

(iii) Organization and Documentation of the Film –

Take into account take-counters, subdivision of films by indication sheets, placement of blips, and documentation on the filming procedure.

Structuring a film by legible indications on the filmed material, running take numbers, blips, and appropriate indications on a take frame.

 

(iv) Choice of the System –

The system should guarantee resolution of at least 120 lp/mm over the entire screen.

The equipment should also include the following: automatic focusing, lighting that adjusts automatically to the material being filmed, a camera head that can turn, adjustable lamps (for lighting book folds), image field projection, adjustable image masking, automatic lighting of blips, and take counters.

For filming books and archival material, the camera should produce optimal results with reduction ratios of between 8 and 24.

For conservation reasons, the planetary camera should also have a device for protecting bindings and book covers, such as a two-part book-cradle with a sufficiently open glass plate with adjustable pressure. It should be possible to film heavier and oversize volumes without damaging them.

For duplicating masters, the film should be silver-halogenide duplicate film of the same polarity. Duplicating should be undertaken with high-quality duplicating equipment (working under vacuum on parallel-running films) to minimize the loss of resolution.

(v) Recommendations for color microfilm –

For digitization of color film should be a high-resolution, permanent-color bleach-fixing-process microfilm on a polyester film base which should yield a high-resolution, reproduction quality microfilm that matches the quality of black-and-white microfilm.

Use the full-step format of un-perforated 35 mm microfilm

Choice of Color film scanners should meet the minimum requirement of digitizing full-step 35 mm color microfilm and should have good resolution support say up to 2000 dots per inch (dpi) or more