1、BRITISH STANDARD BS ISO 18903:2002 Imaging materials Films and paper Determination of dimensional change ICS 37.040.20 BS ISO 18903:2002 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2001 BSI 31 January 2001 ISBN 0 580 41179 6 Na
2、tional foreword This British Standard reproduces verbatim ISO 18903:2002 and implements it as the UK national standard. It supersedes BS ISO 6221:1996 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography, which has the responsibility to
3、: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Co
4、rrespondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does n
5、ot of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developm
6、ents and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to vi, pages 1 to 17 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued sinc
7、e publication Amd. No. Date Comments Reference number ISO 18903:2002(E)INTERNATIONAL STANDARD ISO 18903 First edition 2002-07-01 Imaging materials Films and paper Determination of dimensional change Matriaux pour limage Films et papiers Dtermination des variations dimensionnelles BSISO18903:2002lcsi
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12、yrf ttseuqer eh.re ISO cirypothg fofice saCe tsopale 65 eneG 1121-HC 02 av leT. 4 + 10 947 22 1 11 xaF0 947 22 14 + 9 74 E-mial coirypthgis.oc h Web ww.wiso.ch ii BSISO18903:2002 iiiContents Page Forewordv Introductionvi 1 Scope 1 2 Normative reference1 3 Terms and definitions .1 4 Measurement techn
13、ique3 5 Sampling.3 5.1 Selection of specimens.3 5.2 Handling of specimens .3 5.3 Conditioning of specimens.3 5.4 Processing of specimens .4 6 Conditioning.4 6.1 Constant humidity chamber .4 6.2 Standard temperature and humidity4 7 Test for humidity coefficient of expansion .5 7.1 Procedure .5 7.2 Ca
14、lculations .5 7.3 Test report 5 8 Test for thermal coefficient of expansion .5 8.1 General5 8.2 Procedure .6 8.3 Calculations .6 8.4 Test report 6 9 Test for dimensional change due to processing7 9.1 General7 9.2 Coding system .7 9.3 Procedure .7 9.4 Calculations .8 9.5 Test report 8 10 Test for dim
15、ensional change due to processing plus ageing.8 10.1 Ageing conditions .8 10.2 Ageing time 9 10.3 Procedure .9 10.4 Calculations .9 10.5 Test report 9 BSISO18903:2002iv Annex A (informative) Numbering system for related International Standards .10 Annex B (informative) Methods of measuring dimension
16、al change12 Annex C (informative) Dimensional hysteresis in photographic materials.13 Bibliography 17 BSISO18903:2002 vForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Sta
17、ndards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also
18、take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical committees
19、 is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibi
20、lity that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 18903 was prepared by Technical Committee ISO/TC 42, Photography. This first edition of ISO 18903 cancels and replac
21、es ISO 6221:1996, which has been technically revised. Annexes A to C of this International Standard are for information only. BSISO18903:2002vi Introduction Photographic films and papers exhibit temporary or reversible dimensional changes as well as permanent dimensional changes. This International
22、Standard is designed to provide uniform methods for treating the specimens and for expressing the dimensional changes which occur with changes in atmospheric conditions and those which occur in processing and ageing. Temporary or reversible dimensional changes are the result of changes in the equili
23、brium moisture content (which is determined by the relative humidity of the surrounding atmosphere) or changes in temperature. Permanent dimensional changes occur as the result of processing and ageing. The rate of permanent shrinkage of film generally increases with temperature, but decreases with
24、time. The rate of shrinkage may also be greatest at either high or low relative humidity, depending on the type of film. Some materials, particularly photographic film on polyester base, can show a swelling after a high humidity exposure. The increasing use of photographic films in recent years, in
25、applications where dimensional stability is critical, has emphasized the importance of an accurate measure of dimensional properties. For example, in photomechanical reproductions a dimensional change of as little as 0,01 % may be of practical importance. In the case of aerial mapping, uniform shrin
26、kage is not serious since it can be easily corrected by a change in magnification, but any difference in shrinkage in the two principal directions is a source of error. Any localized or non-uniform changes in dimension are of practical concern. The dimensional change properties of any film or paper
27、depend not only on their composition and method of manufacture, but also on their thermal and moisture content history. Accurate evaluation of such properties requires some control over the specimen history as well as very precise control over the conditioning and measuring procedures. Film and pape
28、r dimensions are also subject to hysteresis effects. These are relatively more important with the more stable materials such as polyester photographic base films. Additional information on the dimensional characteristics of photographic films and papers and on methods of measurement may be found in
29、the bibliography. BSISO18903:2002INTENRATIONAL TSANDADR IS:30981 O2002(E)1Imaging materials Films and paper Determination of dimensional change 1 Scope This International Standard specifies a method for determining the dimensional change of photographic films and papers caused by: variations in equi
30、librium moisture content due to change in the relative humidity (RH) of the atmosphere (humidity coefficient of expansion); change in temperature (thermal coefficient of expansion); processing; ageing. This International Standard deals with the moisture content and thermal history of the specimens b
31、efore measurement, the atmospheric conditions during measurement, and the treatment of the data. It does not describe the various experimental techniques used to make the measurements. This International Standard is not suitable for determining the dimensional change of instant photographic film. 2
32、Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreement
33、s based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of c
34、urrently valid International Standards. ISO/TR 18931:2001, Imaging materials Recommendations for humidity measurement and control 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 conditioning exposure of a specimen to air at a gi
35、ven relative humidity and temperature until equilibrium is reached 3.2 differential dimensional change difference between the dimensional changes of the material in the two principal directions (length and width) NOTE Polyester-based films frequently have maximum and minimum dimensional changes in d
36、irections other than the length or width. These can be determined by rotating and viewing the uncoated base between a pair of crossed polarizers. BSISO18903:20022 When the direction corresponding to either the maximum or minimum dimensional change is coincident with the optical axis of one polarizer
37、, there is minimum light transmission through the base. 3.3 dimensional change due to processing permanent dimensional change caused by photographic processing NOTE This may be the conventional wet chemical processing, vapour processing or heat processing. It is measured after conditioning at the sa
38、me relative humidity and temperature as used for the original measurement and is expressed as a percentage. 3.4 dimensional change due to processing plus ageing permanent dimensional change that occurs as a result of processing plus ageing of the processed material NOTE It is measured after conditio
39、ning of the processed, aged film or paper at the same relative humidity and temperature as used for the original measurement and is expressed as a percentage. 3.5 dimensional hysteresis difference in the absolute dimensions of a specimen in equilibrium with air at a given relative humidity, when con
40、ditioned from a higher relative humidity and when conditioned from a lower relative humidity NOTE See annex C. 3.6 humidity coefficient of expansion change in dimension per unit length per 1 % change in relative humidity at constant temperature 3.7 humidity expansion contraction dimensional change c
41、aused by the gain (or loss) of moisture following changes in the relative humidity of the ambient air at constant temperature 3.8 length direction direction of the film or paper parallel to its forward movement in the film- or paper-making machine NOTE This is also termed “grain” or “machine directi
42、on” in the case of papers. 3.9 preconditioning establishment of a moisture content history by conditioning the specimen at a relative humidity above or below the conditioning relative humidity used for measurement NOTE The purpose of preconditioning is to control the effects of hysteresis (see 3.5).
43、 3.10 thermal coefficient of expansion change in dimension per unit length per 1 C change in temperature at constant relative humidity 3.11 thermal expansion contraction dimensional change caused by a rise (or fall) of temperature at constant relative humidity NOTE This is an apparent thermal expans
44、ion, since the moisture content of film varies slightly with temperature at constant relative humidity. However, the primary effect is thermal expansion. Thermal expansion is less important for paper because of the small changes involved, particularly compared to humidity effects. BSISO18903:2002 33
45、.12 width direction direction of the film or paper at right angles to the length direction NOTE This is also termed “cross direction”. 4 Measurement technique There are a number of different techniques used for measuring the dimensional change of sensitized materials. Specifications of measuring equ
46、ipment are beyond the scope of this International Standard, but several approaches are described in annex B. 5 Sampling 5.1 Selection of specimens Specimens intended for dimensional stability tests shall exhibit no obvious physical defects, be representative of the whole of the material being tested
47、, be handled in the same manner as in actual use, and be treated uniformly. When different materials are to be compared, they shall have been subjected to the same conditioning history. The length direction should be indicated if known. 5.2 Handling of specimens Specimens shall be prepared under con
48、trolled conditions and then separated into groups which are subjected to different atmospheric conditions. The operator shall take care not to breathe on the specimens and shall wear moisture-resistant gloves while handling them, since moisture from the skin may reduce the accuracy of the results. 5
49、.3 Conditioning of specimens 5.3.1 General Specimens shall be suspended in the conditioning atmosphere by means of a hook or a rod through a hole in the middle of one end near the edge of the specimen. The specimens shall be separated to prevent contact with each other. An alternative method of conditioning is to place specimens in racks spaced so that there is free circulation of the air on both sides of the material. Specimens shall not be removed from the co
