5.1 Lightfastness of printed ink jet media for specified periods of time is pertinent to the end use of these materials. Since the ability of ink jet prints to withstand color changes is a function of the spectral power distribution of the light source to which it is exposed, it is important that lightfastness be assessed under the conditions appropriate to the end use application. While ink jet prints may be handled and displayed under a variety of conditions, this practice is intended to produce the color changes that may occur in ink jet prints upon exposure to irradiation from office lighting where overhead fluorescent light is used for illumination by simulating these conditions.

5.2 The accelerated procedures covered in this practice are intended to provide a means for the rapid evaluation of the relative lightfastness of a series of prints or of a print of interest in comparison to the performance of controls with known lightfastness exposed simultaneously under laboratory conditions. Test results are useful for specification acceptance between producer and user, for quality control, and for research and product development.

5.3 Variation in results may be expected when operating conditions are varied within the accepted limits of this practice. For example, differences in the level of irradiance using lamps with the same spectral power distribution can cause significant differences in test results. Therefore, no reference to the use of this practice should be made unless accompanied by a report prepared in accordance with Section 12 which specifies whether Test Method D4674 Method II or Method III was used and which describes the specific operating conditions used.

5.4 Reproducibility of test results between laboratories using the same method (e.g., Method II or Method III of Test Method D4674 ) has been shown to be good when the stability of materials is evaluated in terms of performance ranking compared to other materials or to a control. Therefore, exposure of a similar material of known performance (a control) at the same time as the test materials is strongly recommended. It is recommended that at least three replicates of each material be exposed to allow for statistical evaluation of results.

5.5 Color changes may not be a linear function of duration of exposure. The preferred method of determining lightfastness is to expose the prints for a number of intervals and to assess the exposure duration required to obtain a specific color change.

1.1 This practice covers an accelerated procedure intended to determine the lightfastness of ink jet prints in office environments where overhead fluorescent light is used for illumination.

1.2 This practice describes two methods based on Method II and Method III from D4674 , in which specimens are exposed to cool white VHO fluorescent lamps (Method II) and cool white fluorescent lamps (Method III) under controlled environmental conditions.

1.3 Two criteria are used to determine relative lightfastness: color change and optical density.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8 .

1.5 There is no known ISO equivalent standard.