ISO 18937:2020 pdf free.Imaging materials – Photographic reflection prints – Methods for measuring indoor light stability.
This document specifies a set of recommended test methods with associated requirements for permitted reporting. Data from these tests shall not be used to make life expectancy claims, such as time-based print lifetime claims, either comparative or absolute. Conversion of data obtained from these methods for the purpose of making public statements regarding product life shall be in accordance with the applicable documents for specification of print life. .
The test methods in this document may be useful as stand-alone test methods for the absolute or
comparative stability of image materials with respect to colour fading or measurement of physical
properties. Caution shall be used when comparing test results for different materials. Comparisons shall be limited to test cases using test apparatus with matching specifications and matching test conditions.
No accelerated laboratory exposure test can be specified as a total simulation of actual use conditions. Results obtained from these laboratory accelerated exposures can be considered as representative of actual use exposures only when the correlation has been established for the specific materials being tested and when the type of degradation is the same. The relative durability of materials in actual use conditions can be very different in different locations because of differences in radiant energy (both in spectral irradiance and intensity), relative humidity, temperature, pollutants such as ozone, and other factors. Print image stability results from this test method, especially in terms of the amount of acceleration and/or correlation to end-use service life, that are determined for one printer model, software settings, colourant, and media combination should not be applicable to another printer model, software settings, colourant, and media combination.
5 Test methods — General
5.1 Safety cautions
In light stability tests, a high irradiance level is used, often with significant UV content. Special care shall be taken to avoid eye injury or skin erythema. Precautions should be taken to ensure that the light source cannot inadvertently be viewed without suitable eye and skin protection.
5.2 Light source and filters
This document references the use of a filtered xenon-arc light source (daylight behind window glass) as described in ISO 4892-2 for accelerated tests with the intention of reproducing as closely as possible different end-use lighting conditionsUilIiJ. In addition, special filtering of the xenon-arc lamp is used (which is not referenced in ISO 4892-2) to achieve the lighting conditions applicable to this method.
5.3 Humidity control
The relative humidity of the air circulating the test chamber shall be controlled. The location of sensors used for measuring humidity shall be as specified in ISO 4892-1.
5.4 Temperature control
Uninsulated black metal panels are used to indirectly control specimen temperature. The black panel shall be constructed in accordance with ISO 489 2-1 and mounted at the specimen exposure plane. The uninsulated black panel shall be controlled.
Chamber (ambient) temperature shall be controlled. The sensor shall be shielded from light and mounted near the exposure zone.
Most lightfastness apparatus use ambient laboratory air to control chamber air temperature. Therefore, laboratory conditions shall be maintained such that the apparatus can control temperature effectively. Air refrigeration units may be required to maintain the chamber air temperature depending on the laboratory air temperature.
NOTE The ± tolerances given for testing set points are the allowable fluctuations of the parameter about the given value under equilibrium conditions. This does not mean that the apparatus set point value can be varied by ± the amount indicated from the given value, just that the measured value may. These ± tolerances are also not intended as requirements for chamber uniformity.ISO 18937 pdf download.