1、Designation: E 883 02 (Reapproved 2007)Standard Guide forReflectedLight Photomicrography1This standard is issued under the fixed designation E 883; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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. Scope1.1 This guide outlines various methods which may befollowed in
3、 the photography of metals and materials with thereflected-light microscope. Methods are included for prepara-tion of prints and transparencies in black-and-white and incolor, using both direct rapid and wet processes.1.2 Guidelines are suggested to yield photomicrographs oftypical subjects and, to
4、the extent possible, of atypical subjectsas well. Information is included concerning techniques for theenhanced display of specific material features. Descriptivematerial is provided where necessary to clarify procedures.References are cited where detailed descriptions may behelpful.1.3 This standar
5、d does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use. Specific precau-tionary state
6、ments are given in X1.7.1.4 The sections appear in the following order:Referenced documents 2Terminology 3Significance and use 4Magnification 5Reproduction of photomicrographs 6Optical systems 7Illumination sources 8Illumination of specimens 9Focusing 10Filters for photomicrography 11Illumination te
7、chniques 12Instant-processing films 13Photographic materials 14Photographic exposure 15Photographic processing 16Keywords 17Suggestions for visual use of metallographic microscopes AppendixX1Guide for metallographic photomacrography AppendixX2Electronic photography AppendixX32. Referenced Documents2
8、.1 ASTM Standards:2E 3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to MetallographyE 175 Terminology of MicroscopyE 768 Guide for Preparing and Evaluating Specimens forAutomatic Inclusion Assessment of SteelE 1951 Guide for Calibrating Reticles and Light Micro-scope Magn
9、ifications3. Terminology3.1 DefinitionsFor definitions of terms used in this guide,see Terminologies E7and E 175.4. Significance and Use4.1 This guide is useful for the photomicrography andphotomacrography of metals and other materials.4.2 The subsequent processing of the photographic materi-als is
10、also treated.5. Magnification5.1 Photomicrographs shall be made at preferred magnifi-cations, except in those special cases where details of themicrostructure are best revealed by unique magnifications.5.2 The preferred magnifications for photomicrographs, are:253,503,753, 1003, 2003, 2503, 4003, 50
11、03, 7503,8003, and 10003.5.3 Magnifications are normally calibrated using a stagemicrometer. Calibration procedures in Guide E 1951 should befollowed.6. Reproduction of Photomicrographs6.1 Photomicrographs should be at one of the preferredmagnifications. A milli- or micrometre marker shall be super-
12、imposed on the photomicrograph to indicate magnification, ina contrasting tone. The published magnification, if known,should be stated in the caption.1This guide is under the jurisdiction ofASTM Committee E04 on Metallographyand is the direct responsibility of Subcommittee E04.03 on Light Microscopy
13、.Current edition approved May 1, 2007. Published May 2007. Originallyapproved in 1982. Last previous edition approved in 2002 as E 883 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
14、information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Photomicrograph captions should include basic back-ground information (for example, material identificat
15、ion,etchant, mechanical or thermal treatment details) and shouldbriefly describe what is illustrated so that the photomicrographcan stand independent of the text.6.3 Arrows or other markings, in a contrasting tone, shall beused to designate specific features in a photomicrograph. Anymarking used sha
16、ll be referenced in the caption.7. Optical Systems7.1 Microscope objectives are available in increasing orderof correction as achromats, semiapochromats (fluorites) andapochromats (see Terminologies E7and E 175). Plan objec-tives are recommended for photographic purposes becausetheir correction prov
17、ides a flatter image. The objective lensforms an image of the specimen in a specific plane behind theobjective called the back focal plane. (This is one of severalpossible real image planes, called intermediary planes, wherereticles may be inserted as optical overlays on the image.)7.2 The eyepiece
18、magnifies the back focal plane (or other)intermediary image for observation or photomicrography. Eye-pieces are sometimes also used to accomplish the full correc-tion of the objectives spherical aberration and to improve theflatness of field.7.2.1 The pupil of the observers eye must be brought tocoi
19、ncidence with the eyepoint of the visual eyepiece to viewthe entire microscopical image. High-eyepoint eyepieces arenecessary for eyeglass users to see the entire image field.7.2.2 Most microscopes have built-in photographic capa-bilities that use an alternate image path through the microscopeleadin
20、g to a camera attachment port or to a viewscreen. Aprojection eyepiece delivers the image to the camera port orscreen.7.3 Intermediate lenses (relay or tube lenses) are oftenrequired to transfer the specimen image from the intermediaryplane of the objective to that of the eyepiece. They may alsoadd
21、their own magnification factor, either fixed or as a zoomsystem.7.4 The objective, the eyepiece, and the compound micro-scope (including any intermediate lenses) are designed as asingle optical unit. It is recommended to use only objectivesand eyepieces which are intended for the microscope in use.7
22、.5 The resolution of the microscope depends primarily onthe numerical aperture of the objective in use (1)3. The termempty magnification is used to describe high magnifications(above approximately 1100 times the numerical aperture of anobjective), which have been shown to offer no increase inimage r
23、esolution. Nevertheless, some types of information,such as the distance between two constituents, may be moreeasily obtained from microstructures examined at moderateempty magnifications.8. Illumination Sources8.1 Metallographic photomicrography typically uses Khlerillumination. To obtain Khler illu
24、mination, an image of thefield diaphragm is focused in the specimen plane, and an imageof the lamp filament or arc is focused in the plane of theaperture diaphragm. Specific steps to obtain Khler illumina-tion vary with the microscope used. The manufacturersinstructions should be followed closely.8.
25、2 For incandescent lamps, the applied voltage determinesthe unit brightness and the color temperature of the source.Evaporated tungsten blackens the envelope, resulting in dimin-ished brightness and color temperature as the lamp ages.Tungsten-halogen lamps minimize envelope blackening, main-taining
26、constant brightness and color temperature for most oftheir life. The high brightness and 3200 K color temperature ofthese lamps makes them especially suitable for color photomi-crography.8.3 With arc sources, brightness per unit area is substan-tially higher than that from any incandescent source. T
27、heirspectral output contains high energy spikes superimposed on awhite-light continuum. They also contain significant ultraviolet(UV) and infrared (IR) emissions that should be removed foreye safety (and for photographic consistency, with UV); see8.4, 11.3.1, and 11.5.2.8.3.1 Xenon arcs produce a sp
28、ectral quality close to daylight(5600K), with a strong spike at 462 nm. Strong emissions inthe IR should be removed. Xenon arcs that do not produceozone are recommended.8.3.2 Carbon arcs have a continuous output in the visibleportion of the spectrum, with a color temperature near 3800Kand a strong e
29、mission line at 386 nm.8.3.3 Mercury arcs have strong UV and near-UV output,and are particularly useful to obtain maximum resolution witha blue filter. The color quality is deficient in red; it cannot bebalanced for color photomicrography.8.3.4 Zirconium arcs have strong spectral output lines in the
30、near IR, requiring filtration. Within the visible region, they arerated at 3200K color temperature.8.4 Arc lamps require heat protection for filters and otheroptical components, and certainly for eye safety. Infraredremoval may be obtained by: “hot” mirrors in the illuminationbeam to reflect IR whil
31、e transmitting visible light; heat-absorbing filters to transmit visible light while absorbing IR,for example, solid glass filters or liquid-filled cells.8.5 A detailed discussion of illumination sources and thequality of illuminants is given by Loveland (2).8.6 Some advice on using metallographic m
32、icroscopes forvisual observation has been compiled in Appendix X1.9. Illumination of Specimens9.1 Photomicrographs are made with a compound micro-scope comprised at least of an objective lens and an eyepiecewith a vertical illuminator between them. Field and aperturediaphragms, with a lamp and lamp
33、condenser lenses, areintegral parts of the system. The microscope should allowsufficient adjustment to illuminate the field of view evenly andto completely fill the back aperture of the objective lens withlight.9.2 The vertical illuminator is a thin-film-coated plane glassreflector set at 45 to the
34、optical axis behind the objective. Itreflects the illumination beam into the objective and transmits3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.E 883 02 (2007)2the image beam from the objective to the eyepiece. In somemicroscopes prism systems are
35、used to perform this function.9.3 The field diaphragm is an adjustable aperture whichrestricts the illuminated area of the specimen to that which is tobe photographed. It eliminates contrast-reducing stray light.The field diaphragm is also a useful target when focusing alow-contrast specimen.9.4 The
36、 aperture diaphragm establishes the optimum bal-ance between contrast, resolution, and depth of field. It shouldbe set to illuminate about 70 % of the objectives aperturediameter. This can be observed by removing the eyepiece andinspecting the back of the objective, either directly or with apinhole
37、eyepiece. The aperture diaphragm should never beused as a light intensity control.9.5 See Fig. 1 for an illustration of a typical verticalillumination system.10. Focusing10.1 Sharp focus is necessary to obtain good photomicro-graphs.10.2 There are two systems for obtaining sharp focus:ground-glass f
38、ocusing and aerial image focusing.10.2.1 For ground-glass focusing, relatively glare-free sur-roundings and a magnifier up to about 33 are required. Tofocus, the focusing knob is oscillated between underfocus andoverfocus in succeedingly smaller increments until the image issharp.10.2.2 There are fo
39、ur possible variations for focusing anaerial image.10.2.2.1 The simplest case is a transparent spot on aground-glass containing a fiduciary mark in the film plane. Thespecimen image is focused to coincide with the fiduciary mark,using a magnifying loupe of about 33 to 53. When the focusis correct, t
40、he specimen image and the fiduciary mark will notmove with respect to each other when the operators head ismoved.10.2.2.2 Asecond case uses a reticle fixed within the opticalsystem at an intermediary plane. Focusing is a two-stepprocess: focus the eyepiece on the reticle; bring the image intofocus a
41、gainst the reticle figure.10.2.2.3 In the third case, a reticle is inserted into a focusingeyepiece. Depending on equipment used, this can be either atwo or three-step process: focus the reticle within the eyepiece;next, set the proper interpupiliary distance, if required (someequipment requires a s
42、pecific interpupiliary distance for eye-piece focus to coincide with camera focus); then focus theimage coincident with the reticle.10.2.2.4 The fourth case uses a single-lens reflex camerabody, where the camera focusing screen is the plane ofreference. An eyepiece magnifier for the camera is an imp
43、or-tant accessory for this case. An aerial image focusing screen ispreferred.10.3 The critical focus point is affected by both the principalillumination wavelength in use and the size of the aperturediaphragm. Final focusing should be checked with all filters,apertures, and other components set for
44、the photomicrograph.11. Filters for Photomicrography11.1 Photomicrographs require filtration of the light source.This section describes filter types and their uses.11.2 Each filter selectively removes some wavelengths fromthe transmitted beam of light. Two types of filters, interferenceand absorptio
45、n, can be used for this purpose.11.2.1 Interference filters act as selective mirrors. By meansof coatings on a glass substrate, they selectively transmitcertain wavelengths while reflecting all others. These filtersmay be used in high-energy light beams. The mirrored side ofthe filter should face th
46、e light source. (The hot mirrors in 8.4are interference filters.)11.2.2 Absorption filters are dyed substrates of glass, plas-tic, or gelatine. They absorb some wavelengths of light andtransmit the balance. Through their absorption, they canbecome overheated and damaged if placed in high-energy ligh
47、tbeams without protection. The usual protection is either aninterference filter or a liquid-filled cell placed in the beamFIG. 1 Vertical Illuminating System for a Metallurgical MicroscopeE 883 02 (2007)3before the absorption filter. Wratten gelatine filters are usedbelow as examples (3). Many simil
48、ar glass and plastic filtersare also available.11.3 Certain general purpose filters have application in bothcolor and black-and-white photomicrography.11.3.1 Ultraviolet light can be removed with an interferencefilter, a glass or gel filter from the Wratten #2 series, or a liquidcell filled with a s
49、odium nitrite solution (2 % NaNO2is usedfor a 1-cm path. It should be proportionately stronger orweaker for other cell path lengths). Ultraviolet light must beremoved from arc lamps for eye safety, and should be removedfor color photomicrography, as explained in 11.5.2.11.3.2 Gray neutral density filters reduce the intensity of alight beam equally across the visible spectrum. They are madein interference and absorption types in many different densi-ties, for example, the Wratten #96 series. They are useful foreyepiece work with an arc source, and to modify the brightness
