There are three different kinds of photographic films/plates: SR films, HR films and nuclear plates (NP). They differ in their resolution, their exposure times and in the developing process.
 

SR films: grain size approximately 4-5 mm. exposure times for topography are usually between 0.1 s and several seconds.

HR films: grain size smaller than 1 mm. Exposure time 200 times the exposure time for an SR film.

NP: there are NPs with different emulsion thickness (25 mm and 50 mm). The grain size is around 1 mm. The exposure time is 1.6 times (for 50 mm) or 1.8 times (for 25 mm) the exposure time for the SR films.

 

Charging the envelopes with new films:

SR and HR films do not have the same size. There are plastic envelopes of the right size for each one of them (the longer ones are for the HR films). There are paper envelopes for exposures using low energy X-rays, where absorption by the plastic envelopes is too high.

 

1 SR films (Kodak Industrex SR)

 

SR films can be found in either of the refrigerators in the dark room. They are packed in yellow and black cardboard boxes and in paper envelopes. A protecting paper is placed around each individual film. The films have a blue side that is dark in the red light of the dark room and a brighter side. The brighter side carries the emulsion. Place the film with its protecting paper in the plastic envelope putting the emulsion side away from the Velcro band. In that way, the film can be exposed with the emulsion side towards the X-ray beam and with the closing lid behind the film.

 

2 HR films (Slavich)

 

The films are packed in gray cardboard boxes and in several cardboard envelopes but not protected by a sheet of paper. There is no color difference between the emulsion and the other side of the film. When you open the last envelope and you place it with the longer side of the lid downwards, the emulsion side is upwards. You can check the emulsion side by scratching the film in a corner while looking at the reflection of the red lamp on the film. When you scratch the emulsion side, the trace of the scratch is visible. Take an old protecting paper of a SR film, place it around the HR film and put it in an adequate envelope with the emulsion side away from the Velcro band.

 

3 Nuclear Plates (Ilford)

 

Nuclear Plates are stored in small white cardboard boxes. The emulsion side is less brilliant than the other side when looking at the reflection of the red lamp. If you are not sure which side is the emulsion, you can do the same check as with HR films. Use old protecting papers of SR films to cut pieces of the proper size to protect the NP. Put an aluminum foil over the protecting paper (at least on the emulsion side) and insert all in the soft plastic envelopes for the NP. Close the envelope (on the side opposite to the emulsion) with adhesive tape.

The aluminum foil protects the NP against the diffuse scattering of X-rays in air.

Development of the films:

Films and NPs are numbered in a standard way on ID19. The number of a film consists of the date plus a serial number of two digits in the format YYMMDD##. The 24th film taken on the 15th of march 2001 would therefore be numbered 01031524. The number is scratched into the emulsion of the film/NP in the right upper corner when looking at the film parallel to the incident X-ray beam.

The SR and HR films can be developed using the Kodak developing machine. Place the emulsion to the top when you introduce the film. This is especially important for the HR films, because if you put the film in the wrong orientation, the developing machine will damage the emulsion, which results in additional artificial contrast on your images.

The nuclear plates can be developed using the 'home made' developing machine (for details see documentation of the development machine).

In case of need HR films and NPs can be developed 'by hand'.