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HOME > FILM > BPFB-18 FILM
Film: BPFB-18 Film
Blue-sensitive film of moderately high contrast. It can
be used for copying continuous-tone B&W pictures and for making high-light
masks. BPFB is especially useful, however, for making
both interpositives and, subsequently, duplicate negatives from original
B&W negatives. This two-step duplicating process allows great control
over the quality of the final negative and permits the making of either
same-sized duplicates (by contact), or enlarged negatives. Enlarged duplicate
negatives are commonly used in alternative processes (platinium, palladium,
gelatine and gum bichromate printing, print-out paper etc..), for all
of these processes require a film ‘’at’’ the finished
size.
Color Sensitivity
The
emulsion, being blue sensitive, has a maximum sensitivity of about 450
nm.
Safelight
Red
safelight, as from a 15 w lamp fitted with a Wratten 1A filter and placed
1 meter from the workbench, works well for laboratory lighting. It is
a good idea from time to time to test for safelight fogging.
Exposure
The
following exposure values will vary from one user to the next, and are
offered only as suggestions : For copywork of documents, using two
1000w Xenon lamps at a distance of 1 meter , or two 45 A arc lamps :
20 seconds at f/ 64
For contact printing, the exposure time is about 7 seconds using diffused
lighting. If the light intensity of the contact printer is adjustable,
it should be at 20 lux/second.
Development
Any good, standard continuous tone film developer, in
tray, machine, or tank, can be used to develop BPFB-18.
Fixing and Washing
After
development, the use of an acid stop bath is recommended as it will help
preserve the fixer. Minimum fixing time in a fresh fixer should be 7 minutes
for a normal fixer, and 5 minutes in a rapid fixer.
Storage
BPFB-18 films must be kept in a cool and dry place, ideally
at a temperature not exceeding 21°C (68° F), and at a relative
humidity of 50%.
Note: While Bergger Products Inc have made every
effort to ensure the accuracy of this data, it is always advisable to
run some tests of your own before developing important work. Please use
these times as starting points only. Data like this should always be treated
as guidelines because of the tremendous number of variables involved.
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