What is black-film substitution?
As a rule, four colours are used for printing. (The CMYK method involves cyan, magenta, yellow and black and these are the basic colours used for four-colour printing.)
A printing plate is required to print each of these colours and this plate contains a certain number of pages (depending on the size of the printing press used).
For a four-colour catalog with 1440 pages of A4 where a 16-page printed sheet is used, this means:
- 8 pages per printing plate = 16 pages per print sheet (front and back)
- Per print sheet, 8 printing plates, four each for the front and back (CMYK in each case)
- Ninety print sheets are required for 1440 pages: this makes 720 printing plates
In order to produce ten foreign-language versions, without black-film substitution the number of printing plates required would be: 720 + 720 x 10 languages = 7920 printing plates.
With black-film substitution the procedure is different: three colour plates (CMY) are used from the master language. Then the only new plates required are the black plates and these are then inserted in the printing machine.
This requires 720 printing plates for the master language and 180 black printing plates for each foreign language = 720 + 10 x 180 black plates = 2520 printing plates.
The effect this has on cutting costs is obvious when one bears in mind that each printing plate costs around 60 euros. Further savings are achieved by reducing set-up times on the printing press.
Essential requirement for the typesetting/layout system
For black-film substitution the layout for one language must act as the master in the typesetting/layout system when producing pages. This master defines the status of all elements on the pages. All language-related elements must be managed variably and can practically be exchanged with the corresponding foreign-language content.
A key factor here is that the status of the elements that are not related to language is not changed in any way at all on the page for all languages. To do this, the layout system must have the capability to differentiate between fixed and variable elements and to protect the fixed elements to prevent them from being changed.
Manual reworking of the layout when producing the foreign-language documents must be kept to the absolute minimum. A large amount of additional effort to rework the layout on foreign-language documents will wipe out most of the cost benefits gained through black-film substitution!Through generating the foreign-language versions in this way the FinalCatalogs system achieves over 90% efficiency in spite of the high density of information in the catalog documents. This means that over 90% of generated documents are created so that they fit automatically and no further corrections are required in the layout.