ISO 7004:2002 pdf free.Photography — Industrial radiographic films — Determination of ISO speed, ISO average gradient and ISO gradients G2 and G4 when exposed to X- and gamma-radiation.
This International Standard specifies methods for measuring the ISO speed, SO average gradient and ISO gradients G2 and G4 of industrial radiographic film systems when exposed directly to X- and y-radiation. Many countries have had national standards relating to this subject for many years and may provide values which are different from those obtained by following the procedure specified in this International Standard. Because the photographic characteristics of a film system are dependent on the energy distribution in the wavelength spectrum four representative sources are specified for determining sensitometric characteristics. To minimize the differences between national standards an this International Standard, the minimum requirements for X-ray tubes and X-ray generators have been considered mandatory and have been clearly specified in the subclause on radiation quality 5.3.3).This International Standard imposes limiting specifications on the thickness of the metallic screens often used in conjunction with the film as specified in the basic rules for good radiographic practice in ISO 5579.
Photographic results are also dependent on the chemical process used to develop the film. This International Standard does not attempt to specify the processing method; therefore, when ISO speed or ISO gradient values are given for a film system, it is necessary to specify not only the radiation quality used but also the process. This will permit the comparison of systems consisting of film and film processing.
ISO 7004:2002 specifies methods for determining sensitometric curve shape, ISO speed, ISO average gradient and ISO gradients G2 and G4 for industrial radiographic systems consisting of film and film processing when exposed directly to X-rays and gamma-rays. The measurement of characteristics of film systems used in industrial radiography with fluorescent intensifying screens is not specified in this International Standard.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 5-2: 2001, Photography — Density measurements — Part 2: Geometric conditions for transmission density ISO 5-3:1995, Photography — Density measurements — Part 3: Spectral conditions
ISO 4037-1:1996, X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy — Part 1: Radiation characteristics and production methods
ISO 5579: 1998, Non-destructive testing — Radiographic examination of metallic material by X- and gamma rays — Basic rules
4 Sampling and storage
In determining the sensitometric curve, ISO speed, ISO average gradient and ISO gradients G2 and G4 of a film system, it is important that the samples evaluated yield the average results obtained by users. This will require evaluating several different batches periodically under conditions specified in this International Standard. Prior to evaluation, the samples shall be stored according to the manufacturer’s recommendations for a length of time that simulates the average age at which the product is normally used. Several independent evaluations shall be made to ensure the proper calibration of equipment and processes. The basic objective in selecting and storing samples as described above is to ensure that the film characteristics are representative of those obtained by a consumer at the time of use.
5 Method of test
5.1 Principle
Samples are exposed and processed as specified in 5.3 and 5.4. Measurements are obtained from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO speed, ISO average gradient and ISO gradients G2 and G4.
5.2 Safelights
To eliminate the possibility of safelight illumination affecting the sensitometric results, all films shall be handled in complete darkness during exposure and processing.
5.3 Exposure
5.3.1 Film holders
Film/screen combinations shall be exposed in holders which provide less than 2 Yo absorption of the radiation specified (without taking into account lead screens).
5.3.2 Sample condition
During exposure, the samples shall be at a temperature of 23 °C ± 5 °C and in equilibrium with air at a relative humidityof 50%±20%.ISO 7004:2002 pdf free download.