ISO 18939:2013 pdf free

ISO 18939:2013 pdf free.Imaging materials一Digital hard copy for medical imaging一Methods of measuring permanence
The film shall be examined under the magnification and lighting conditions that are normal for the intended use of the product. The emulsion layer or backing layer of the processed film shall be examined for layer separation, edge peeling and delaminating that can impair its intended use. Other phenomena relating to changes in colour, visual density or surface characteristics, such as gloss, smudge, and defects introduced upon humidity cycling shall not be reported.
Binder stability is tested by the wedge brittleness test as outlined in ISO 18907. Physical aging can cause differences in the brittleness behaviour (or flexibility) of both emulsion and backing layers and can lead to brittle failure during handling of large-sized radiographic films. The wedge brittleness measurements shall be made on five unheated and five heated specimens of processed film, with the sample heating procedure representing an accelerated simulation of binder ageing. Each specimen shall preferably contain a low-density area. Although the dimensions of the processed film specimen are not critical, one dimension shall preferably be at least 350 mm, but at least 150 mm in length in order to comply with the brittleness test ISO 18907. Five film specimens shall be subjected to accelerated ageing as described in 4.3.2.
Processed film shall be subjected to accelerated ageing conditions to meet the requirements for binder stability. The test specimens shall be conditioned at23±2 °Cand 50±5 % relative humidity for at least 15 h. After conditioning, place the specimens in a moisture-proof envelope and heat-seal the envelope.
NOTE 1 A suitable moisture-proof envelope is a metal foil bag that is coated on the inside with polyethylene for heat sealing.
To prevent sticking between adjacent specimens, it may be necessary to interleave them with aluminium foil. Ensure a high ratio of film to air volume by squeezing out excess air prior to heat-sealing. Use a separate envelope for each film sample. Heat the envelopes in an oven for two weeks at (60±2 °C).
NOTE 2 Incubation is accomplished in a closed environment to prevent escape of any decomposition products that may be produced during incubation. Such products may catalyse further degradation of the film base.ISO 18939 pdf download.