|ILFORD Type RX Recording Film|
|The following information
originated from Sue, of Harman Technology, in response to a query
by David Mittelstadt (member of the APUG forum website) who wanted
to know the original use of a roll of bulk film (400 feet
left out of an original 1,000ft - 300m - length, on a 2"
core) that he had purchased. No ASA speed or processing data
was marked on David's film packaging.
Sue's information is presented here for future reference.
Although Sue's information correctly refers to Type RX film (expiry date 1964) as owned by David Mittelstadt, Michael Talbert found reference in a 1967 Ilford catalogue, to an Improved Type RX film.
RX recording film
Ferranti phosphors A (equivalent
to the American P24), C, G, H and J all give good exposure response,
particularly the A and C phosphors for short persistence.
RX may be processed to a negative record but is particularly suitable for processing to a silver halide reversal positive. It is used in conjunction with the RPI equipment to provide rapid access of subjects such as racecourse finishes.
RX is coated on a 0.13mm (5/1000 inch) safety base, permanently grey-dyed for anti-halation purposes.
The high contrast resolving
power of RX when processed to a negative by the methods given
below (under Processing) is as follows:-
Safelights - It is sensitive to light of all colours and should be handled in total darkness. A 908 (very dark green) safelight can be used to help during development stages, but needs to be used with a lot of care.
Exposure - Using high quality cathode ray tubes
with a final anode potential of 15kV and a beam current of 0.5
to 1.0µA, RX film can record, at a lens aperture of f1.4,
a writing speed on the film of 10,000 cm per second.
Processing - The processing of RX is achieved
most rapidly in the Kelvin Hughes and other types of rapid access
Michael Talbert adds: