ASTM E1815-18(2023)
(Test Method)Standard Test Method for Classification of Film Systems for Industrial Radiography
Standard Test Method for Classification of Film Systems for Industrial Radiography
SIGNIFICANCE AND USE
4.1 This test method provides a relative means for classification of film systems used for industrial radiography. The film system consists of the film and associated processing system (the type of processing and processing chemistry). Section 9 describes specific parameters used for this test method. In general, the classification for hard X-rays, as described in Section 9, can be transferred to other radiation energies and metallic screen types, as well as screens without films. The usage of film system parameters outside the energy ranges specified may result in changes to a film/system performance classification.
4.1.1 The film performance is described by contrast and noise parameters. The contrast is represented by gradient and the noise by granularity.
4.1.2 A film system is assigned a particular class if it meets the minimum performance parameters: for Gradient G at D – D0 = 2.0 and D – D0 = 4.0, and gradient/noise ratio at D – D0 = 2.0, and the maximum performance parameter: granularity σD at D = 2.0.
4.2 This test method describes how the parameters shall be measured and demonstrates how a classification table can be constructed.
4.3 Manufacturers of industrial radiographic film systems and developer chemistry will be the users of this test method. The result is a classification table as shown by the example given in Table 2. Another table also includes speed data for user information. Users of industrial radiographic film systems may also perform the tests and measurements outlined in this test method, provided that the required test equipment is used and the methodology is followed strictly. (A) Family of films ranging in speed and image quality.
4.4 The publication of classes for industrial radiography film systems will enable specifying bodies and contracting parties to agree to particular system classes, which are capable of providing known image qualities. See 8.2.
4.5 ISO 11699–1 and European standard EN 584-1 describe the same m...
SCOPE
1.1 This test method covers a procedure for determination of the performance of film systems used for industrial radiography. This test method establishes minimum requirements that correspond to system classes.
1.2 This test method is to be used only for direct exposure-type film exposed with lead intensifying screens. The performance of films exposed with fluorescent (light-emitting) intensifying screens cannot be determined accurately by this test method.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1815 − 18 (Reapproved 2023)
Standard Test Method for
Classification of Film Systems for Industrial Radiography
This standard is issued under the fixed designation E1815; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ISO Standards:
ISO 5-2 Photography Density Measurements—Part 2: Geo-
1.1 This test method covers a procedure for determination
metric Conditions for Transmission Density
of the performance of film systems used for industrial radiog-
ISO 5-3 Photography and Graphic Technology—Density
raphy. This test method establishes minimum requirements that
Measurements—Part 3: Spectral Conditions
correspond to system classes.
ISO 7004 Photography—Industrial Radiographic Films, De-
1.2 This test method is to be used only for direct exposure-
termination of ISO Speed, ISO average gradient and ISO
type film exposed with lead intensifying screens. The perfor-
gradients G2 and G4 When Exposed to X and Gamma
mance of films exposed with fluorescent (light-emitting) inten-
Radiation
sifying screens cannot be determined accurately by this test
ISO 11699-1 Non-Destructive Testing—Industrial Radio-
method.
graphic Film—Part 1: Classification of Film Systems for
Industrial Radiography
1.3 The values stated in SI units are to be regarded as
standard. The values given in parentheses are for information ISO 11699-2 Non-Destructive Testing—Industrial Radio-
graphic Film—Part 2: Control of Film Processing by
only.
Means of Reference Values
1.4 This standard does not purport to address all of the
ISO/IEC 17025 General Requirements for the Competence
safety concerns, if any, associated with its use. It is the
of Testing and Calibration Laboratories
responsibility of the user of this standard to establish appro-
2.3 European CEN Standard:
priate safety, health, and environmental practices and deter-
EN 584-1 Non-Destructive Testing—Industrial Radio-
mine the applicability of regulatory limitations prior to use.
graphic Film—Part 1: Classification of Film Systems for
1.5 This international standard was developed in accor-
Industrial Radiography
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3. Terminology
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.1 Definitions—For definitions of terms used in this test
Barriers to Trade (TBT) Committee. method, refer to Terminology E1316.
3.2 Definitions of Terms Specific to This Standard:
2. Referenced Documents
3.2.1 characteristic curve—curve showing the relationship
2.1 ASTM Standards:
between the common logarithm of exposure logK, and the
E94 Guide for Radiographic Examination Using Industrial
optical density D.
Radiographic Film
3.2.2 diffuse density—quantitative measure of film blacken-
E1316 Terminology for Nondestructive Examinations
ing (optical density) as determined by a densitometer. It is the
sum of all transmitted and scattered light into the half sphere
This test method is under the jurisdiction of ASTM Committee E07 on
behind the film.
Nondestructive Testing and is the direct responsibility of Subcommittee E07.01 on
3.2.3 film gradient G—the slope of the characteristic curve
Radiology (X and Gamma) Method.
Current edition approved June 1, 2023. Published June 2023. Originally
at a specified optical density, D, and a measure of the contrast
approved in 1996. Last previous edition approved in 2018 as E1815 – 18. DOI:
of the film system.
10.1520/E1815-18R23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1815 − 18 (2023)
TABLE 1 Limiting Values for Gradient, Gradient/Granularity Ratio, and Granularity
Minimum Gradient G at Minimum Maximum
Gradient/ Granularity,
ASTM
Granularity σ , at D = 2.0
D
System
Ratio, G/σ , above D
D o
D = 2.0 D = 4.0
Class
at D = 2.0
above D above D
o o
above D
o
Special 4.5 7.5 300 0.018
I 4.1 6.8 150 0.028
II 3.8 6.4 120 0.032
III 3.5 5.0 100 0.039
W-A 3.8 5.7 135 0.027
W-B 3.5 5.0 110 0.032
W-C <3.5 <5.0 80 0.039
The classification is only valid for the complete film system. In general, the classification for X-rays as described in 7.1 can be transferred to other
radiation energies and metallic screen types as well as films without screens and single coated films.
A certificate shall contain the following information:
–reference to this standard
–date
–measured values of gradient at D = 2 and D = 4 above fog and base
–measured granularity at D = 2 above fog and base
–calculated value of (D/σ ) at D = 2 above fog and base
D
–Dose K for D = 2 above fog and base
S
–Processing conditions:
–Manual or automatic
–Type of chemistry
–Developer immersion time
–Developer temperature
–Classification in accordance with Table 1
Table 2 gives an example for a classification result of different film types, a developer system and given developing conditions.
3.2.4 film system—the film and associated film-processing 4. Significance and Use
requirements in accordance with the criteria established by the
4.1 This test method provides a relative means for classifi-
manufacturers of the film and processing chemicals.
cation of film systems used for industrial radiography. The film
3.2.5 film system class—classification taking into account of
system consists of the film and associated processing system
limiting values given in Table 1.
(the type of processing and processing chemistry). Section 9
3.2.6 gradient/noise ratio—ratio of the gradient G and the describes specific parameters used for this test method. In
granularity σ . It relates directly to the signal/noise ratio. All general, the classification for hard X-rays, as described in
D
further parameters determining the signal, such as the modu- Section 9, can be transferred to other radiation energies and
lation transfer function or the energy of the radiation, are metallic screen types, as well as screens without films. The
considered to be constant. usage of film system parameters outside the energy ranges
3.2.6.1 Discussion—The limiting values given in this stan-
specified may result in changes to a film/system performance
dard are related to fixed radiation energies and specified classification.
screens.
4.1.1 The film performance is described by contrast and
noise parameters. The contrast is represented by gradient and
3.2.7 granularity, σ —stochastic fluctuation in a radio-
D
graphic image, superimposed on the image of the object and the noise by granularity.
typically caused by random, statistical groupings of individual
4.1.2 A film system is assigned a particular class if it meets
silver particles in processed film.
the minimum performance parameters: for Gradient G at
D – D = 2.0 and D – D = 4.0, and gradient/noise ratio at
3.2.8 ISO speed S—reciprocal value of the dose K mea- 0 0
S
D – D = 2.0, and the maximum performance parameter:
sured in Gray, which results in a specified diffuse optical
granularity σ at D = 2.0.
transmission density D – D = 2 on the processed film, where D
D is the fog and base density:
4.2 This test method describes how the parameters shall be
1 measured and demonstrates how a classification table can be
S 5 (1)
K constructed.
S
3.2.9 signal/noise ratio—in industrial radiography, the ratio
4.3 Manufacturers of industrial radiographic film systems
of a local film density to the granularity σ at this density level.
D
and developer chemistry will be the users of this test method.
It is correlated to the gradient/noise ratio.
The result is a classification table as shown by the example
3.2.10 specular density—quantitative measure of film given in Table 2. Another table also includes speed data for
blackening (optical density) when light passing the optics of a user information. Users of industrial radiographic film systems
microdensitometer transmits the film. may also perform the tests and measurements outlined in this
E1815 − 18 (2023)
TABLE 2 Typical Film System Classification
Automatic Film Processing
Developer: Type A
Developer immersion time: XXX seconds
Developer temperature: XX°C/YY°F
Minimum
Minimum Gradient G at
Gradient/ Maximum
ASTM System Granularity Granularity, σ , ISO Speed Dose, K , m Gy,
A D s
Film Type
Class Ratio, G/σ , at at D = 2.0 above S D = 2.0
D
D = 2.0 D = 4.0
D = 2.0 above D
o
above D above D
o o
D
o
A Special 5.4 9.1 360 0.015 32 29.0
B I 4.5 8.4 281 0.016 64 14.0
C I 4.4 7.6 232 0.019 100 8.7
D I 4.4 7.6 169 0.026 200 4.6
E II 4.4 7.6 142 0.031 320 3.2
F III 4.0 5.2 114 0.035 400 2.5
G W-A 4.2 6.5 225 0.019 100 8.6
H W-B 4.1 5.3 170 0.025 200 5.0
A
Family of films ranging in speed and image quality.
test method, provided that the required test equipment is used frequency corresponding to the first zero in the spatial fre-
and the methodology is followed strictly. quency response of the circular aperture. Mathematical proce-
dures that can be shown to produce equivalent reductions in the
4.4 The publication of classes for industrial radiography
effects of system artifacts are acceptable alternatives to the use
film systems will enable specifying bodies and contracting
of this filter (see 7.3).
parties to agree to particular system classes, which are capable
of providing known image qualities. See 8.2.
6. Sampling and Storage
4.5 ISO 11699–1 and European standard EN 584-1 describe
6.1 For product specification it is important that the samples
the same method for classification of film systems for industrial
evaluated yield the average results obtained by users. This will
radiography, but its class definitions and number of classes do
require the evaluation of several different batches periodically
not align exactly with this test method. International users of
under conditions specified in this standard. Prior to evaluation,
these standards should be aware of these differences for their
the samples shall be stored according to the manufacturers’
particular applications.
recommendations for a length of time to simulate the average
NOTE 1—ASTM research report E07–1005 contains documentation of
age at which the product is normally used. The basic objective
technical methods used during the development of this test method.
in selecting and storing samples as described above is to ensure
5. Microdensitometer Requirements the film characteristics are representative of those obtained by
a consumer at the time of use.
5.1 The influx aperture of the microdensitometer shall be
approximately circular in shape, with a diameter (referred to
7. Test Method
the plane of the specimen) not less than 1.2× or more than 2×
the diameter of the efflux aperture.
7.1 Preparation:
7.1.1 The film samples shall be exposed to X-rays from
5.2 The reduction of the influx aperture by the influx optics
tungsten target tubes. Inherent filtration of the tube, plus an
and the magnification of the specimen onto the efflux aperture
additional copper filter located as close to the X-ray tube target
by the efflux optics shall lie in the range from 20× to 100×. The
as possible shall provide filtration equivalent to (8.00 6 0.05)
two magnifications need not be equal.
mm of copper. The potential across the X-ray tube shall be
5.3 The efflux (or measuring aperture) shall be preferably
adjusted until the half-value-absorption is obtained with (3.5 6
circular in shape. Its effective diameter referred to the speci-
0.2) mm of copper. A potential of approximately 220 kV
men plane shall be 100 μm 6 5 μm.
generally meets this requirement.
5.4 The spectral response of the microdensitometer system
7.1.2 The film system shall include a front and a back screen
shall be visual, as specified by ISO 5-3.
of 0.02 mm to 0.04 mm lead. If single coated films are used,
5.5 An electronic band-pass filter, used to reduce the un-
the emulsion coated surface shall face the X-ray tube. Good
wanted signal caused by system artifacts, shall have its
film screen contact shall be ensured.
low-frequency boundary set so the system response is 3 dB
7.1.3 Exercise care to ensure that the film specimen does not
down at a temporal frequency corresponding to a spatial
contain density variations arising from the exposing equipment
frequency of 0.1 cycles/mm. Its high-frequency boundary shall
(such as non-uniform beam filters or damaged, or defective
be set so that the system response is 3 dB down at a temporal
lead screens) or processing system. During and after exposure,
prior to processing, maintain the film specimen at the tempera-
ture of 23 °C 6 5 °C and relative humidity of 50 % 6 20 %.
Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Reports RR:E07-1005 and RR:E07-1007. The film processing chemicals and procedures shall be the
E1815 − 18 (2023)
same for determining gradient and granularity, and they shall microdensitometer. Both emulsion layers shall be recorded;
be used and described completely as specified. this means that the depth of focus of the microdensitometer has
to include both layers.
7.1.4 Use manufacturer certified film test strips in accor-
dance with ISO 11699-2 to test the specified developer system
7.3.2 The granularity value shall be determined in terms of
with the specified immersion time and developer temperature.
diffuse density.
The speed index S shall be within 65 % of the manufacturer’s
x
7.3.3 If the optical density is measured as specular density,
certificate. The developer temperature may differ by 61 °C
it shall be converted into diffuse optical density, using the plot
from the certified value to adjust S within 65 % of the
X
of the curve of diffuse density versus specular density at the
manufacturer certificate value. The obtained S and used
X
mean density value of the granularity film specimen. The
developer temperature shall be documented in the test report.
diffuse density of each step shall be measured with the
This test shall be done, on a daily basis, before and afte
...
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