ISO 18909 is a standard published by the International Organization for Standardization (ISO) that provides methods for measuring the image stability of processed photographic color films and prints on paper. The purpose of this standard is to provide a standardized method for assessing the long-term stability of photographic images, especially in archiving and preservation applications.
The standard outlines several different methods for measuring image stability, including using accelerated aging tests that simulate long-term exposure to heat, humidity, and light. The standard also includes guidance for measuring changes in color, density, and other physical properties of photographic images over time.
ISO 18909 provides guidance on test sample preparation and handling, including sample size and shape and test conditions. The standard also provides guidance for the selection of test equipment and procedures, including the type of equipment required for testing and the procedures for conducting the tests.
The standard recommends testing using a controlled environment, including controlled temperature, humidity and lighting conditions. The standard also provides guidance on calibration and verification of test equipment to ensure accurate and reliable test results.
ISO 18909 provides specific measurement methods for evaluating the image stability of color film and paper prints. For color films, the standard recommends the use of a Spectrophotometer to measure the change in color over time. The standard provides guidelines for selecting appropriate measurement parameters such as wavelength range and measurement interval.
For paper prints, the standard recommends the use of a densitometer to measure changes in density and color. The standard also provides guidelines for selecting appropriate measurement parameters, such as measurement aperture and measurement interval.
ISO 18909 includes information on calculating and reporting test results, including the use of statistical methods to analyze and compare data. The standard provides guidelines for reporting image stability test results, including calculating and reporting various parameters such as color shift, density change, and image fading.
ISO 18909 is an important standard for the photographic industry, especially for those involved in the preservation and archiving of photographic material. By following the guidelines set forth in this standard, photographers, curators and archivists can ensure that their photographic material is properly assessed for image stability and can be preserved for future generations.
Overall, ISO 18909 is an important standard for assessing the long-term stability of photographic images, especially in archival and preservation applications. By following the guidelines set forth in the standard, photographers, conservators and archivists can ensure their photographic material is well preserved and can be enjoyed for years to come.
