HDI - Jackets and Combi-Jackets

Jackets and Combi-Jackets

'Microfilm' is a generic word describing several types of photographic negatives, all of which are used, for storing small images of pages, drawings etc. When the negatives are stored in cellophane holders, they are known as Jackets. When two different sizes of film are stored in the same jacket, they are known as Combi-Jackets. Both of these, and all other types of film, can be scanned successfully.

For text and lineart, scanning at one bit depth is required together with a resolution of 200 ppi at the final image size. Black and white photographs require scanning in greyscales, normally at eight bit depth, resulting in 256 shades of grey. Resolution providing 200 ppi at the final image size is required for grey scale scanning.

Jackets

A 'Jacket' is a cross between rolled film and fiche and comprises a cellophane holder in which strips of film are inserted. In a normal 'Jacket', the film strips are all the same size resulting in something similar in appearance to a fiche. The individual image sizes are typically 8mm x 14mm.

Combi-Jackets

In a 'Combi-Jacket' one strip is used for nominal 35mm (30mm x 40/45mm) size film and the remainder used for filmstrip containing smaller images size 10mm x 15mm. As with the standard fiche, the number of images can vary. Architects, Engineers, Local Authorities or anyone, who builds up project files with a mixture of drawings, calculations, correspondence, plans, etc commonly used this type of microfilm.