1、Designation: E312 06 (Reapproved 2011)Standard Practice forDescription and Selection of Conditions for PhotographingSpecimens Using Analog (Film) Cameras and Digital StillCameras (DSC)1This standard is issued under the fixed designation E312; the number immediately following the designation indicate
2、s the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONPhotographs are often used to convey informati
3、on about the appearance of objects, materials, orphenomena involved in testing. The appearance of a photograph of an object depends not only on theappearance of the object, but on the conditions of formation of the optical image, the conditions offormation of the photographic record, and the conditi
4、ons of viewing the photograph. If thephotographic method of recording appearance is to be reproducible from one laboratory to another andif photographs of various specimens or one specimen at various times are to be used for validcomparisons, there must be an established method of describing pertine
5、nt conditions, so they may berecorded, communicated, and standardized. The purpose of this practice is to provide such a methodof description.1. Scope1.1 This practice defines terms and symbols and provides asystematic method of describing the arrangement of lights,camera, and subject, the character
6、istics of the illumination, thenature of the photographic process, and the viewing system.Conditions for photographing certain common forms of speci-mens are recommended.Although this practice is applicable tophotographic documentation in general, it is intended for use indescribing the photography
7、of specimens involved in testingand in standardizing such procedures for particular kinds ofspecimens. This practice is applicable to macrophotographybut photomicrography is excluded from the scope of thispractice.1.2 This standard does not purport to address all of thesafety concerns, if any, assoc
8、iated 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1535 Practice for Specifying Color by the Munsell SystemE
9、284 Terminology of AppearanceE1360 Practice for Specifying Color by Using the OpticalSociety of America Uniform Color Scales SystemE1541 Practice for Specifying and Matching Color Usingthe Colorcurve System (Withdrawn 2007)32.2 ANSI Standards:4ANSI/ISO 517-1996 Apertures and Related Properties Per-t
10、aining to Photographic LensesDesignations and Mea-surementsISO 3664:2000 Viewing ConditionsGraphic Technologyand PhotographyISO 18920:2000 Imaging Materials Processed PhotographicReflection Prints Storage Practices1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance
11、and is the direct responsibility of Subcommittee E12.03 on Geometry.Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 1966. Last previous edition approved in 2006 as E312 06. DOI:10.1520/E0312-06R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
12、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards In
13、stitute (ANSI), 25 W. 43rd St.,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 StatesNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM I
14、nternational (www.astm.org) for the latest information1ISO 6846:1992 Black-and-White Continuous Tone PapersDetermination of ISO Speed and Range for Printing3. Terminology3.1 DefinitionsAppearance terms used in this practiceconform to definitions in Terminology E284. Terms related tophotography confo
15、rm to the cited standards of the AmericanNational Standards Institute.4. Significance and Use4.1 This practice provides a basis for choosing, specifying,recording, communicating, and standardizing the conditionsand processes that determine the nature of a photographicimage of a specimen. Its provisi
16、ons are particularly usefulwhen the photographic image is used to preserve or commu-nicate the appearance of a specimen involved in an aging orstressing test that affects its appearance. It is often useful tocompare photographs made under identical conditions beforeand after a test to illustrate a c
17、hange in appearance.4.2 This practice deals with specific details of cameratechnique and the photographic process, so it will probably bebest understood and implemented by a technical photographeror someone trained in photographic science. The personrequiring the photograph must clearly indicate to
18、the photog-rapher what features of the specimen are of technical interest,so he may use techniques that make those features clearlyevident in the photograph, without misrepresenting the appear-ance of the specimen.4.3 This practice provides useful guidance on presentingphotographs for viewing, provi
19、ding an indication of dimen-sions or scale, indicating the orientation of the picture, andreferring to particular points on a picture. These techniquesshould be useful to those writing technical literature involvingillustrations of the appearance of specimens. The methods ofthis practice should cont
20、ribute materially to the accuracy andprecision of other standards that rely on pictures to indicatevarious grades of some attribute of appearance, such asblistering or cracking.4.4 For acceptance testing, manufacturing control, and regu-latory purposes, it is desirable to employ measurement, but int
21、hose cases where there are no methods of measuring theattribute of appearance of interest, well-made photographs orphotomechanical reproductions of them may be the bestavailable way to record and communicate to an inspector thenature of the attribute of appearance.5. Descriptors for Conditions5.1 Pr
22、imary Points:5.1.1 Central Image Point, IThe geometrical center of thepicture area on the film or plate, designated by the symbol I(see Fig. 1).FIG. 1 Coordinate System for Specifying the Geometric Relationship of Camera, Subject, and LightingE312 06 (2011)25.1.2 Nodal Points, H, HThe two points H a
23、nd Hinthelens system, located on the line joining the centers of curvatureof the elements and having the property that any ray from theobject directed toward H emerges from H parallel to theoriginal path. The nodal point with respect to rays from theobject is called the “first nodal point” and is de
24、signated by thesymbol H while the nodal point with respect to rays directed tothe image is called the “second nodal point” and is designatedby the symbol H.5.1.3 Central Object Point, OThe point in the objectspace that is imaged at the central image point, designated bythe symbol O. (It is not neces
25、sary that any material thing existat this point.)5.2 Primary Axes:5.2.1 Camera AxisThe straight line between the centralimage point and the second nodal point. The distance betweenthese points is called the “axial image distance” and isdesignated by the symbol v.5.2.2 Optical AxisThe straight line j
26、oining the centers ofcurvature of the elements of the lens.5.2.3 Field AxisThe straight line between the centralobject point and the first nodal point. The distance betweenthese points is called the “axial object distance” and isdesignated by the symbol u.5.3 Reference Planes:5.3.1 Image Reference P
27、laneThe plane normal to thecamera axis, passing through the central image point.5.3.2 Lens Reference PlaneThe plane normal to the fieldaxis, passing through the first nodal point.5.3.3 Object Reference PlaneThe plane normal to the fieldaxis, passing through the central object point.5.4 Orientations:
28、5.4.1 Film OrientationThe film or detector orientation isdescribed in a right-handed orthogonal coordinate systemhaving x and y axes in the image reference plane and z axis onthe camera axis, with the positive direction away from the lens.A film plane is described by the angles of a direction vector
29、making an angle g with the z axis and having a projection onthe image reference plane making an angle h with the x axis.5.4.2 Lens OrientationThe lens orientation is described ina right-handed orthogonal coordinate system having xLand yLaxes in the lens reference plane and zLaxis on the field axis,w
30、ith the positive direction toward the object space. The xLaxisis parallel to the x axis and the yLaxis is parallel to the y axis.The lens orientation is described by the angles of a directionvector making an angle k with the zLaxis and having aprojection on the lens reference plane making an angle l
31、 withthe xLaxis.5.4.3 Object OrientationThe object orientation is de-scribed in a right-handed orthogonal coordinate system havingx and y axes in the object reference plane and z axis on the fieldaxis, with the positive direction toward the lens. The x axis isparallel to the x axis and the y axis is
32、 parallel to the y axis.Anobject plane can be described in terms of the angles of adirection vector making an angle i with the z axis and havinga projection on the object reference plane making an angle jwith the x axis. Since an object plane may or may not passthrough the central object point, the
33、intersection of the planewith the z axis must be stated. If a cylindrical coordinate isfound useful, the distance from a point to the z axis measuredalong the normal to the z axis may be designated by the symbolp. If there are a number of planes or points to be specified, theycan be numbered and the
34、 coordinates given numerical sub-scripts accordingly, for example, x1,x2,x3,i1,i2,p1,p2, etc.5.4.4 Illuminant OrientationThe geometrical aspect of theillumination is described with respect to the same coordinatesystem used for describing the orientation of the object. Thecenter or centroid of a ligh
35、t source is designated by the symbolL, with the appropriate subscript when more than one lightsource is used. The distance between the central object pointand the center of a light source is designated by the symbol r,with the appropriate numerical subscript. The direction of thelight from the point
36、 O is described in terms of the angles of adirection vector making an angle a with the z axis and havinga projection on the object reference plane making an angle bwith the x axis, or, alternatively, making an angle c with the yzplane (the angle c being positive on the positive x side) and anangle e
37、 with the xz plane (the angle e being positive on thepositive y side). The diameter of the lamp reflector is desig-nated by the symbol d, with appropriate subscript. The coor-dinates (x, y) of the point on the object reference plane towardwhich the lamp reflector is directed must be given.The size a
38、ndshape of the lamp and reflector must be described withsufficient precision for the intended purpose.5.5 Spectral Nature of IlluminationIncandescent lampsmay be specified adequately by stating the kind of illuminant,the rated color temperature, and the electrical potential, involts, at which the la
39、mps are operated. The correlated colortemperature of these lamps increases about 11 K for each voltincrease in applied potential, in the neighborhood of 115 V. Aslamps are used, the correlated color temperature (at a givenvoltage) decreases, often from 50 K above to 50 K below therated value during
40、the life of the lamp. Fluorescent lamps, arcs,and flash lamps differ more than incandescent lamps fromblack-body spectral emittance and must be described in detailas to make, model, type, etc. The nature of reflectors, includingincidental nearby surfaces, can have an important effect on thespectral
41、nature of the energy falling on the object. Theneutrality of such surfaces should be specified when spectralquality is of interest.5.6 Contrast:5.6.1 Object-Surround ContrastThe appearance of an ob-ject may depend on the contrast between the object and thebackground or other visual surroundings agai
42、nst which theobject is seen. The orientation of the background or surround-ing materials may be described in the same way as theorientation of the object and the reflection characteristics of thematerials appearing with the object may be completely speci-fied. However, it is usually more convenient
43、to specify the ratioof the luminance of the object to the luminance of thebackground or other surroundings, as measured from thedirection of the camera lens by a photographic exposure meter.If constant contrast is desirable, it may be specified in that wayE312 06 (2011)3but it should be noted that t
44、he use of constant contrast tends tominimize the visual appreciation of the variation of lightnessamong specimens.5.6.1.1 If the object-surround contrast is specified for somestandard object, it will vary from one specimen to another,according to the lightness of the specimen. A matte, neutral-gray
45、card of specified reflectance may serve as the standardobject. Such a neutral test card with a diffuse reflectance of18 % on one side and 90 % on the other is sold by dealers inphotographic supplies.5The placement of the test card in theobject space must be specified.5.6.2 Illumination ContrastThe a
46、ppearance of an objectmay depend on the ratio of illuminances produced at the objectby the various sources of illumination. This effect is mostnoticeable when surface texture is of interest. The ratios maybe conveniently specified by the ratio of luminances producedby the sources separately on a mat
47、te, neutral-gray test card inthe object space. The ratio of luminances can be measured witha photographic exposure meter. The exact value of the reflec-tance of the test card is immaterial for the purpose, as long asthe card reflects enough light for accurate measurement.However, the surface must re
48、flect diffusely. The placement ofthe test card in the object space and the point at which themeasurement is made must be specified. Normally the cardwould be placed in the object reference plane and the mea-surement would be made at the point O.5.7 PolarizationUnwanted specular reflections from theo
49、bject are often avoided by the use of polarizers between thelamps and the object and a polarizing filter placed over thecamera lens, or both. Since the use of such polarizers may havea pronounced effect on the appearance of an object as depicted,polarizers should be used in specimen photography only whenrequired to depict the object most effectively, and in every casethe usage should be clearly specified.5.8 Focal Length of LensOne of the principal character-istics of a photographic lens is its focal length (equivalent focallengt
