Non-destructive testing - Industrial radiographic film - Part 1: Classification of film systems for industrial radiography
1 Scope
The purpose of this part of GB/T 19348 is to establish the performance of film systems.
This part is applicable for the classification of film systems in combination with specified lead screens for industrial radiography (non-destructive testing). This part is intended to ensure that the image quality of radiographs - as far as this is influenced by the film system - is in conformity with the requirements of other standards such as ISO 5579, ISO 17636 and EN 12681.
This part does not apply to the classification of films used with fluorescent intensifying screens. The measurement of film systems in this part is restricted to a selected radiation quality to simplify the procedure. The properties of films will change with radiation energy, but not the ranking of film system quality.
Additional methods for evaluating the photographic process are described in GB/T 19348.2, by which the performance of film systems may be controlled under the conditions given in industry.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 19348.2 Non-destructive testing - Industrial radiographic films - Part 2: Control of film processing by means of reference values
GB/T 27025 General requirements for the competence of testing and calibration laboratories
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
film system
combination of film and film processing which is carried out in accordance with the instructions of the film manufacturer and/or the manufacturer of the processing chemicals
3.2
film gradient
slope of the characteristic curve of a film at a specified optical density D
3.3
granularity
stochastic density fluctuations in the radiograph, superimposed on the image of the object
Note: The limiting values given in this part of GB/T 19348 are related to fixed radiation energies and specified screens.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Sampling and storage
5 Test method
5.1 Preparation
5.2 Measurement of gradient G
5.3 Measurement of granularity σD
5.4 Measurement of ISO speed S
5.5 Other equipment and procedures
6 Limiting values for classification
Bibliography
Table 1 Limiting values for gradient, gradient/noise-ratio and granularity
Table 2 Determination of ISO speed S from dose KS needed for a film density D=2 above D0
