ASTM E883-02(2007)
(Guide)Standard Guide for Reflected–Light Photomicrography
Standard Guide for Reflected–Light Photomicrography
SIGNIFICANCE AND USE
This guide is useful for the photomicrography and photomacrography of metals and other materials.
The subsequent processing of the photographic materials is also treated.
SCOPE
1.1 This guide outlines various methods which may be followed in the photography of metals and materials with the reflected-light microscope. Methods are included for preparation of prints and transparencies in black-and-white and in color, using both direct rapid and wet processes.
1.2 Guidelines are suggested to yield photomicrographs of typical subjects and, to the extent possible, of atypical subjects as well. Information is included concerning techniques for the enhanced display of specific material features. Descriptive material is provided where necessary to clarify procedures. References are cited where detailed descriptions may be helpful.
1.3 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 and health practices and determine the applicability of regulatory requirements prior to use. Specific precautionary statements are given in X1.7.
1.4 The sections appear in the following order:Referenced documents2Terminology3Significance and use4Magnification5Reproduction of photomicrographs6Optical systems7Illumination sources8Illumination of specimens9Focusing10Filters for photomicrography11Illumination techniques12Instant-processing films13Photographic materials14Photographic exposure15Photographic processing16Keywords17Suggestions for visual use of metallographic microscopesAppendix X1Guide for metallographic phhotmacrographyAppendix X2Electronic photographyAppendix X3
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E883 – 02 (Reapproved 2007)
Standard Guide for
Reflected–Light Photomicrography
This standard is issued under the fixed designation E883; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 2. Referenced Documents
1.1 This guide outlines various methods which may be 2.1 ASTM Standards:
followed in the photography of metals and materials with the E3 Guide for Preparation of Metallographic Specimens
reflected-light microscope. Methods are included for prepara- E7 Terminology Relating to Metallography
tion of prints and transparencies in black-and-white and in E175 Terminology of Microscopy
color, using both direct rapid and wet processes. E768 Guide for Preparing and Evaluating Specimens for
1.2 Guidelines are suggested to yield photomicrographs of Automatic Inclusion Assessment of Steel
typical subjects and, to the extent possible, of atypical subjects E1951 GuideforCalibratingReticlesandLightMicroscope
as well. Information is included concerning techniques for the Magnifications
enhanced display of specific material features. Descriptive
3. Terminology
material is provided where necessary to clarify procedures.
References are cited where detailed descriptions may be 3.1 Definitions—For definitions of terms used in this guide,
see Terminologies E7 and E175.
helpful.
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 This guide is useful for the photomicrography and
responsibility of the user of this standard to establish appro-
photomacrography of metals and other materials.
priate safety and health practices and determine the applica-
4.2 The subsequent processing of the photographic materi-
bility of regulatory requirements prior to use. Specific precau-
als is also treated.
tionary statements are given in X1.7.
1.4 The sections appear in the following order:
5. Magnification
Referenced documents 2
Terminology 3 5.1 Photomicrographs shall be made at preferred magnifi-
Significance and use 4
cations, except in those special cases where details of the
Magnification 5
microstructure are best revealed by unique magnifications.
Reproduction of photomicrographs 6
Optical systems 7
5.2 Thepreferredmagnificationsforphotomicrographs,are:
Illumination sources 8
253,503,753, 1003, 2003, 2503, 4003, 5003, 7503,
Illumination of specimens 9
8003, and 10003.
Focusing 10
Filters for photomicrography 11 5.3 Magnifications are normally calibrated using a stage
Illumination techniques 12
micrometer. Calibration procedures in Guide E1951 should be
Instant-processing films 13
followed.
Photographic materials 14
Photographic exposure 15
Photographic processing 16
6. Reproduction of Photomicrographs
Keywords 17
6.1 Photomicrographs should be at one of the preferred
Suggestions for visual use of metallographic microscopes Appendix
X1
magnifications. A milli- or micrometre marker shall be super-
Guide for metallographic photomacrography Appendix
imposed on the photomicrograph to indicate magnification, in
X2
a contrasting tone. The published magnification, if known,
Electronic photography Appendix
X3
should be stated in the caption.
6.2 Photomicrograph captions should include basic back-
ground information (for example, material identification,
ThisguideisunderthejurisdictionofASTMCommitteeE04onMetallography
and is the direct responsibility of Subcommittee E04.03 on Light Microscopy. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2007. Published May 2007. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1982. Last previous edition approved in 2002 as E883 – 02. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E0883-02R07. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E883 – 02 (2007)
etchant, mechanical or thermal treatment details) and should aperture diaphragm. Specific steps to obtain Köhler illumina-
briefly describe what is illustrated so that the photomicrograph tion vary with the microscope used. The manufacturer’s
can stand independent of the text. instructions should be followed closely.
6.3 Arrows or other markings, in a contrasting tone, shall be 8.2 For incandescent lamps, the applied voltage determines
used to designate specific features in a photomicrograph. Any
the unit brightness and the color temperature of the source.
marking used shall be referenced in the caption. Evaporated tungsten blackens the envelope, resulting in dimin-
ished brightness and color temperature as the lamp ages.
7. Optical Systems
Tungsten-halogen lamps minimize envelope blackening, main-
7.1 Microscope objectives are available in increasing order taining constant brightness and color temperature for most of
their life.The high brightness and 3200 K color temperature of
of correction as achromats, semiapochromats (fluorites) and
apochromats(seeTerminologiesE7andE175).Planobjectives these lamps makes them especially suitable for color photomi-
are recommended for photographic purposes because their crography.
correctionprovidesaflatterimage.Theobjectivelensformsan 8.3 With arc sources, brightness per unit area is substan-
image of the specimen in a specific plane behind the objective tially higher than that from any incandescent source. Their
calledthebackfocalplane.(Thisisoneofseveralpossiblereal spectral output contains high energy spikes superimposed on a
image planes, called intermediary planes, where reticles may white-lightcontinuum.Theyalsocontainsignificantultraviolet
be inserted as optical overlays on the image.) (UV) and infrared (IR) emissions that should be removed for
7.2 The eyepiece magnifies the back focal plane (or other) eye safety (and for photographic consistency, with UV); see
intermediary image for observation or photomicrography. Eye- 8.4, 11.3.1, and 11.5.2.
pieces are sometimes also used to accomplish the full correc-
8.3.1 Xenonarcsproduceaspectralqualityclosetodaylight
tion of the objective’s spherical aberration and to improve the (5600K), with a strong spike at 462 nm. Strong emissions in
flatness of field.
the IR should be removed. Xenon arcs that do not produce
7.2.1 The pupil of the observer’s eye must be brought to ozone are recommended.
coincidence with the eyepoint of the visual eyepiece to view
8.3.2 Carbon arcs have a continuous output in the visible
the entire microscopical image. High-eyepoint eyepieces are
portion of the spectrum, with a color temperature near 3800K
necessary for eyeglass users to see the entire image field.
and a strong emission line at 386 nm.
7.2.2 Most microscopes have built-in photographic capa-
8.3.3 Mercury arcs have strong UV and near-UV output,
bilitiesthatuseanalternateimagepaththroughthemicroscope
and are particularly useful to obtain maximum resolution with
leading to a camera attachment port or to a viewscreen. A
a blue filter. The color quality is deficient in red; it cannot be
projection eyepiece delivers the image to the camera port or
balanced for color photomicrography.
screen.
8.3.4 Zirconium arcs have strong spectral output lines in the
7.3 Intermediate lenses (relay or tube lenses) are often
near IR, requiring filtration. Within the visible region, they are
required to transfer the specimen image from the intermediary
rated at 3200K color temperature.
plane of the objective to that of the eyepiece. They may also
8.4 Arc lamps require heat protection for filters and other
add their own magnification factor, either fixed or as a zoom
optical components, and certainly for eye safety. Infrared
system.
removal may be obtained by: “hot” mirrors in the illumination
7.4 The objective, the eyepiece, and the compound micro-
beam to reflect IR while transmitting visible light; heat-
scope (including any intermediate lenses) are designed as a
absorbing filters to transmit visible light while absorbing IR,
single optical unit. It is recommended to use only objectives
for example, solid glass filters or liquid-filled cells.
and eyepieces which are intended for the microscope in use.
8.5 A detailed discussion of illumination sources and the
7.5 The resolution of the microscope depends primarily on
quality of illuminants is given by Loveland (2).
the numerical aperture of the objective in use (1) . The term
8.6 Some advice on using metallographic microscopes for
empty magnification is used to describe high magnifications
visual observation has been compiled in Appendix X1.
(above approximately 1100 times the numerical aperture of an
objective), which have been shown to offer no increase in
9. Illumination of Specimens
image resolution. Nevertheless, some types of information,
9.1 Photomicrographs are made with a compound micro-
such as the distance between two constituents, may be more
scope comprised at least of an objective lens and an eyepiece
easily obtained from microstructures examined at moderate
with a vertical illuminator between them. Field and aperture
empty magnifications.
diaphragms, with a lamp and lamp condenser lenses, are
integral parts of the system. The microscope should allow
8. Illumination Sources
sufficient adjustment to illuminate the field of view evenly and
8.1 Metallographic photomicrography typically uses Köhler
to completely fill the back aperture of the objective lens with
illumination. To obtain Köhler illumination, an image of the
light.
fielddiaphragmisfocusedinthespecimenplane,andanimage
9.2 The vertical illuminator is a thin-film-coated plane glass
of the lamp filament or arc is focused in the plane of the
reflector set at 45° to the optical axis behind the objective. It
reflects the illumination beam into the objective and transmits
the image beam from the objective to the eyepiece. In some
The boldface numbers in parentheses refer to the list of references at the end of
this standard. microscopes prism systems are used to perform this function.
E883 – 02 (2007)
9.3 The field diaphragm is an adjustable aperture which 10.2.2.3 Inthethirdcase,areticleisinsertedintoafocusing
restrictstheilluminatedareaofthespecimentothatwhichisto eyepiece. Depending on equipment used, this can be either a
be photographed. It eliminates contrast-reducing stray light. two or three-step process: focus the reticle within the eyepiece;
The field diaphragm is also a useful target when focusing a next, set the proper interpupiliary distance, if required (some
low-contrast specimen. equipment requires a specific interpupiliary distance for eye-
9.4 The aperture diaphragm establishes the optimum bal- piece focus to coincide with camera focus); then focus the
ance between contrast, resolution, and depth of field. It should image coincident with the reticle.
be set to illuminate about 70 % of the objective’s aperture 10.2.2.4 The fourth case uses a single-lens reflex camera
diameter. This can be observed by removing the eyepiece and body, where the camera focusing screen is the plane of
inspecting the back of the objective, either directly or with a reference. An eyepiece magnifier for the camera is an impor-
pinhole eyepiece. The aperture diaphragm should never be tant accessory for this case.An aerial image focusing screen is
used as a light intensity control. preferred.
9.5 See Fig. 1 for an illustration of a typical vertical 10.3 Thecriticalfocuspointisaffectedbyboththeprincipal
illumination system. illumination wavelength in use and the size of the aperture
diaphragm. Final focusing should be checked with all filters,
10. Focusing
apertures, and other components set for the photomicrograph.
10.1 Sharp focus is necessary to obtain good photomicro-
11. Filters for Photomicrography
graphs.
10.2 There are two systems for obtaining sharp focus: 11.1 Photomicrographs require filtration of the light source.
ground-glass focusing and aerial image focusing. This section describes filter types and their uses.
10.2.1 For ground-glass focusing, relatively glare-free sur- 11.2 Eachfilterselectivelyremovessomewavelengthsfrom
roundings and a magnifier up to about 33 are required. To the transmitted beam of light. Two types of filters, interference
focus, the focusing knob is oscillated between underfocus and and absorption, can be used for this purpose.
overfocusinsucceedinglysmallerincrementsuntiltheimageis 11.2.1 Interference filters act as selective mirrors. By means
sharp. of coatings on a glass substrate, they selectively transmit
10.2.2 There are four possible variations for focusing an certain wavelengths while reflecting all others. These filters
aerial image. may be used in high-energy light beams. The mirrored side of
10.2.2.1 The simplest case is a transparent spot on a the filter should face the light source. (The hot mirrors in 8.4
ground-glass containing a fiduciary mark in the film plane.The are interference filters.)
specimen image is focused to coincide with the fiduciary mark, 11.2.2 Absorption filters are dyed substrates of glass, plas-
using a magnifying loupe of about 33 to 53. When the focus tic, or gelatine. They absorb some wavelengths of light and
is correct, the specimen image and the fiduciary mark will not transmit the balance. Through their absorption, they can
move with respect to each other when the operator’s head is become overheated and damaged if placed in high-energy light
moved. beams without protection. The usual protection is either an
10.2.2.2 Asecond case uses a reticle fixed within the optical interference filter or a liquid-filled cell placed in the beam
system at an intermediary plane. Focusing is a two-step before the absorption filter. Wratten gelatine filters are used
process: focus the eyepiece on the reticle; bring the image into below as examples (3). Many similar glass and plastic filters
focus against the reticle figure. are also available.
FIG. 1 Vertical Illuminating System for a Metallurgical Microscope
E883 – 02 (2007)
11.3 Certain general purpose filters have application in both available in sets containing various strengths of red, yellow,
color and black-and-white photomicrography. green, cyan, blue, and magenta.
11.3.1 Ultraviolet light can be removed with an interference 11.5.4 The correct color balance for any color film can be
filter, a glass or gel filter from theWratten #2 series, or a li
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