Lead Intensifying Screens are thin sheets of lead foil mounted on card for ease of handling. One is placed on each side of an x-ray film and in close contact with it, inside a cassette or film-holder before exposure.
They are used in most radiographic techniques, excluding some of those employing low kilovoltages, because they reduce the exposure required and improve the quality of the image.
RADAC follows the standards set by Intex (Radiographic) Limited and together these two companies have been Europe’s specialist manufacturer of lead intensifying screens for more than thirty years. The screens are made from the finest available radiographic lead foil, laminated onto flexible white photographic base card.
The Company has wide experience in the field of industrial radiography. Its prime concern is to produce screens of the highest quality. Each screen is visually examined and selected ones are radiographed. This programme of rigorous quality control ensures that RADAC screens are free from defects that could interfere with the interpretation of the film. The lead surface is not covered With a lacquer coating. The specially formulated lead-rich alloy is hard enough not to cause the transfer of deposits onto the film in normal use.
Uncoated lead also has the advantages higher intensification and the absence of problems associated with uneven coating or melting or partial wearing away of the lacquer.
The surface of the lead has a semi-matt finish and the foil is laminated to its backing by means of a fine, even film of a powerful, radio-transparent adhesive.
Lead and card stay firmly laminated for the life of the screen.
The photographic-quality base-card which forms the support is defect-free, strong and flexible. This means that the screens can be bent over and over again to a small radius, without cracking.
The corners of the screens are rounded to a convenient radius to prevent damage to films and cassettes.
Each screen is clearly stamped with the lead thickness. The larger sizes and those for weld radiography are stamped at each end for easy recognition.
RADAC screens are made in sizes for all world markets. Any special size can be made to order.
Standard metric sizes are cut according to BS 3490:1985 and ISO 5655-1982.
The following lead thicknesses (mm) are available: 0.05, 0.1, 0.125, 0.15, 0.2, 0.25, 0.5, 0.75, 1, 1.5, 2 and 3. Pairs of any thickness combination can be supplied.
Intermediate (centre) screens, with foil on each side of a card support, are available with many lead thicknesses. Most commonly they are supplied as 0.1 mm (0.05/0/.05) or 0.2 mm (0.1/0.1) intermediate screens.
Screens are normally sold in packs of five, ten and twenty-five pairs, but those thicker than 0.25 mm are available only in single-pair packs.
In the packs the screens are placed face-to face and held tightly together between pieces of strong card. Stiffening side-pieces are added to twenty-five packs to prevent flexing of the screens.
The outer wrapping is in the form of a PVC envelope, labelled showing size, pack and thickness.
RADAC screens are protected with a peel-off plastic film which ensures that they reach the customer in perfect condition.
It is essential that the film be removed before the screens are used. Otherwise radiographic quality will suffer.