1、STDmANSI IT7.7-ENGL L77b 0724350 053b897 329 I ANSI/NAPM IT9.9-199 for Imaging Materials - Stability of Color Photographic Images - Methods for Measuring This mate ai is reproduced from American National Standard c?7 6 4 , copyright m, with permission of the American National Standards Institute, In
2、c. Not for resale. No part of this publication may be copied or reproduced in any form, electronic retrieval system or otherwise, without the prior written permission of the American National Standards Institute, Inc., 1 1 West 42nd Street, New York, New York 10036. - -A 1 wn American National Stand
3、ards Institute 11 West 42nd Street New York, New York 10036 - STD*ANSI IT9.9-ENGL L77b 072Li1.50 053b81i8 260 ANSVNAPM IT9.9-1996 Revision and redesignation of ANSI IT9.9-1990 American National Standard for Imaging Materials - Stability of Color Photographic Images - Methods for Measuring Secretaria
4、t National Association of Photographic Manufacturers, Inc. Approved August 14, 1996 American National Standards Institute, Inc. STD-ANSI IT7.7-ENGL 377b 0724350 053bALi7 LT7 American National Standard Approval of an American National Standard requires review by ANSI that the requirements for due pro
5、cess, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more
6、 than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone
7、, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any Amer
8、ican National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the
9、 title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National
10、 Standards may receive current information on all standards by calling or writing the American National Standards Institute. Published by American National Standards Institute 11 West 42nd Street, New York, New York 10036 Copyright O 1996 by American Nation- Standards Institute All rights reserved.
11、No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America APS1.5C1296/48 STD*ANSI IT7.7-ENGL 299b 072Li150 053b850 717 = Contents Foreword i 1 Introduction . 1
12、2 Normative references 2 3 Procedures and test equipment 2 4 5 6 Tables 1 Suitable filters for exposing test samples . 12 2 Correction of density measurements for dmin changes . 12 3 Relative spectral transmittance of window glass 13 4 5 6 Page Dark stability tests . 5 Light stability tests . 7 Repo
13、rting the results 11 Relative spectral power distribution for simulated indoor Relative spectral power distribution for F-6 cool white Relative spectral power distribution for incandescent tungsten C.I.E. illuminant A . 16 indirect daylight ID65 14 fluorescent lamps . 15 7 8 9 Figures 1 2 Annexes A
14、The importance of the starting density in the assessment of dye fading and color balance changes in light stability tests . 21 B A method of interpolation for step wedge exposures . 23 C Illustration of Arrhenius calculation for dark stability 24 D “Enclosure effects“ in light stability tests with p
15、rints framed under glass or plastic sheets 28 E Data treatment for the stability of light-exposed color images 30 F Method for power equation dmin correction of reflection print materials 37 G Bibliography 42 Spectral power distribution for outdoor daylight C.I.E. illuminant D65 . 17 100-klux test c
16、onditions 18 Image-life parameters for which times should be reported . 18 Illustrations of densities defined in equations in 3.7 for blue transmis- sion density of a neutral patch of a transparency-type color material 19 illustrations of densities defined in equations in 3.7 for blue reflection den
17、sity of a neutral patch of a reflection-type color material . 20 I STD-ANSI IT9-9-ENGL L99b W 072LiL50 053b851 855 W Foreword (This foreword is not pari of American National Standard This standard deals with measuring the image stability of color photo- graphic materials. The standard is divided int
18、o two parts. The first covers the methods and procedures for predicting the long-term, dark storage sta- bility of color photographic images; the second covers the methods and procedures for measuring the color stability of such images when exposed to light of specified intensities and spectral dist
19、ribution, at specified tem- peratures and relative humidities. Today, the majority of continuous-tone photographs are made with color photographic materials. The length of time that such photographs are to be kept can vary from a few days to many hundreds of years, and the importance of image stabil
20、ity can be correspondingly small or great. Often the ultimate use of a particular photograph may not be known at the out- set. Knowledge of the useful life of color photographs is important to many users, especially since stability requirements often vary depending upon the application. For museums,
21、 archives, and others responsible for the care of color photographic materials, an understanding of the behavior of these materials under various storage and display conditions is essen- tial if they are to be preserved in good condition for long periods of time. The images of most modern color phot
22、ographs are formed by organic cyan, magenta, and yellow dyes that are dispersed in transparent binder layers coat- ed onto transparent or white opaque supports. Color photographic dye images typically fade during storage and display; they will usually also change in color balance because the three i
23、mage dyes seldom fade at the same rate. In addi- tion, a yellowish (or occasionally other color) stain may form and physical degradation may occur, such as embrittlement and cracking of the support and image layers. The rate of fading and staining can vary appreciably and is gov- erned principally b
24、y the intrinsic stability of the color photographic material and by the conditions under which the photograph is stored and displayed. The quality of chemical processing is another important factor. Post-processing treatments, such as application of lacquers, plastic laminates, and retouching colors
25、, also may affect the stability of color materials. The two main factors that influence storage behavior, or dark stability, are the temperature and relative humidity of the air that has access to the pho- tograph. High temperature, particularly in combination with high relative humidity, will accel
26、erate the chemical reactions that can lead to degrada- tion of one or more of the image dyes. Low-temperature, low-humidity storage, on the other hand, can greatly prolong the life of photographic color images. Other potential causes of image degradation are atmo- spheric pollutants (such as oxidizi
27、ng and reducing gases), microorgan- isms, and insects. The stability of color photographs when displayed indoors or outdoors is influenced primarily by the intensity of the illumination, the duration of exposure to light, the spectral distribution of the illumination, and the ambi- ent environmental
28、 conditions. (However, the normally slower dark fading and staining reactions also proceed during display periods and will con- tribute to the total change in image quality.) Ultraviolet radiation is particu- larly harmful to some types of color photographs and can cause rapid fad- ing as well as de
29、gradation of plastic layers such as the pigmented polyethylene layer of RC (resin-coated) paper supports. ANSVNAPM IT9.9-1996) ii STD-ANSI IT9.9-ENGL 377b 0724350 053b852 793 In practice, color photographs are stored and displayed under varying combi- nations of temperature, relative humidity, and i
30、llumination, and for different lengths of time. For this reason, it is not possible to predict precisely the use- ful life of a given type of photographic material unless the specific conditions of storage and display are known in advance. Furthermore, the amount of change that is acceptable differs
31、 greatly from viewer to viewer, and is influ- enced by the type of scene and the tonal and color qualities of the image. After extensive examination of amateur and professional color photographs that have suffered varying degrees of fading or staining, no consensus has been achieved on how much chan
32、ge is acceptable for various image quali- ty criteria. For this reason, this standard does not specify “acceptable” end-points for fading and changes in color balance. Generally, however, the acceptable limits are twice as wide for changes in overall image densi- ty as for changes in color balance.
33、For this reason, different criteria have been used as examples in this standard for predicting changes in image density and in color balance. The actual determination of such changes is made with test strips that have been exposed and carefully processed according to the manufactur- ers recommendati
34、ons to produce at least (1) an area of minimum density (d,), (2) patches of uniform, neutral density of 1.0 above dmin, and (3) uniform density patches of cyan, magenta, or yellow dyes having red, green, or blue densities of 1 .O above dmin. To simplify the preparation of test specimens and the hand
35、ling of data, a starting density of 1 .O above dmi, is specified for both dark and light stabili- ty tests - although it is recognized that the two types of fading generally have dissimilar visual characteristics.) The effects of light fading, both visually and when expressed as a percent density ch
36、ange, tend to be pro- portionally much greater in lower-density portions of an image (e.g., in the range of 0.1-0.5 above dmin) than in high-density areas. Conversely, in dark fading, the visual effects of fading generally are more noticeable in higher densities than in low densities. Density losses
37、 in dark fading, expressed as a percent density change, tend to be more or less equal throughout the entire density range (see annex A). The user may wish to adopt different end-points for light and dark stability tests to take into account the visual differences manifested by these two types of fad
38、ing. Pictorial tests can be helpful in assessing the visual changes that occur in light and dark stability tests, but are not included in this standard because no single scene is representative of the wide variety of scenes actually encountered in photography. In dark storage at normal room temperat
39、ures, most modern color films and papers have images that fade and stain too slowly to allow evaluation of their dark storage stability simply by measuring changes in the specimens over time. In such cases, too many years would be required to obtain meaningful stability data. It is possible, however
40、, to assess in a relatively short time the probable long-term fading and staining behavior at moderate or low temperatures by means of accelerated aging tests carried out at high temperatures. The influence of relative humidity also can be evaluated by conducting the high-temperature tests at two or
41、 more humidity levels. Wilhelm, H. G., Monitoring the Fading and Staining of Color Photographic Prints, Journal of the American institute for Conservation, 21 (1):49-64; 1981. . III STD-ANSI ITS-Y-ENGL 177b 0724150 053b853 b28 D Similarly, information about the light stability of color photographs c
42、an be obtained from accelerated light stability tests. These require special test units equipped with high-intensity light sources in which test strips can be exposed for days, weeks, months, or even years, to produce the desired amount of image fading (or staining). The temperature of the specimens
43、 and their moisture content must be controlled throughout the test period, and the types of light sources must be chosen to yield data that can be cor- related satisfactorily with those obtained under conditions of normal use. Accelerated light stability tests for predicting the behavior of photogra
44、phic color images under normal display conditions may be complicated by “reciprocity failure.” When applied to light-induced fading and staining of color images, reciprocity failure refers to the failure of many dyes to fade, or to form stain, equally when irradiated with high-intensity versus low-i
45、ntensity light, even though the total light exposure (intensity x time) is kept constant through appropriate adjustments in exposure duration.*) The extent of dye fading and stain formation can be greater or smaller under accelerated conditions, depending on the photochemical reactions involved in t
46、he dye degradation, on the kind of dye dispersion, on the nature of the binder material, and on other variables. For example, the supply of oxygen that can diffuse into a photo- graphs image-containing emulsion layers from the surrounding atmosphere may be restricted in an accelerated test (dry gela
47、tin is an excellent oxygen barrier). This may change the rate of dye fading relative to that which would occur under normal display conditions. The magnitude of reciprocity failure is also influenced by the temperature and moisture content of the test specimen. Furthermore, light fading is influence
48、d by the pattern of irradiation - continu- ous versus intermittent - as well as by IighVdark cycling rates. For all of these reasons, long-term changes in image density, color balance, and stain level can be estimated reasonably closely only for conditions simi- lar to those employed in the accelera
49、ted tests, or when good correlation has been confirmed between accelerated tests and actual conditions of use. In order to establish the validity of the new standard methods for evaluat- ing the dark and light stability of different types of photographic color films and papers, the following product types were selected for the tests by the subcommittee that produced this standard: a) Color negative film with incorporated oil-soluble couplers; b) Color reversal film with incorporated oil-soluble couplers; c) Color reversal film with incorporated Fischer-type couplers; d) Color revers
