Measurement of the fading rate of paints

Abstract

Ability to resist fading is a valued property of most paint and textile materials, and therefore improved methods for measuring the course of fading are in demand. Two of the important evidences of the fading of paints, namely change of color and change of gloss, can be measured rapidly by photoelectric methods developed within the past few years. In the present study photoelectric tristimulus measurements of color change and photoelectric measurements of specular-gloss change were used to follow the fading of several paint samples exposed both to outdoor weather and to two machine treatments (A and B) designed to weather the samples at an accelerated rate. With these measurements it was possible to compare numerically the rates of artificial and natural fading of the paints. The data which were obtained show: (1) the treatment used in conjunction with apparatus A caused fading which averaged 20 times as fast as fading outdoors, but the speed-up factor varied from roughly 5 times for one paint to roughly 40 times for another; (2) the treatment used in conjunction with apparatus B caused fading which averaged 5 times as fast as fading outdoors, but the speed-up factor varied from roughly 3 times for one paint to roughly 20 times for another; and (3) for almost every paint tested, the factor relating the speed of fading from treatment in apparatus A to the speed outdoors was more nearly constant through the whole fading process than the corresponding factor for treatment in apparatus B. Thus treatment A not only faded paints faster, but it provided a preview of the course of fading which was usually a better representation of outdoor fading than that provided by treatment B. The data collected during the present study are noteworthy chiefly for the methods they demonstrate. These should be valuable for future studies of the fading of materials and for the examination of methods for accelerating fading.

Circular of the Bureau of Standards no. 478:

“…It is customary practice, however, to make a repeat determination chiefly as a check on clerical errors. 30 The NBS unit has been used in the inspection of working standards of color (such as the Kitchen and Bathroom Accessory Colors) for conformity to a master standard [93,94], in the purchase specification and test of various types of paint, and in studies of the performance of accelerated weathering machines [26]. In general, this unit evaluated by way of the multipurpose reflectometer is in agreement with the results of visual judgment.…”

A Novel Approach to Quantitative Characterization and Visualization of Color Fading

“…This predictive information for specific colorants used in an artwork is very valuable when deciding on a preservation lighting policy [1,7]. Characterization of color fading and its rate determination as a function of aging conditions are of strong interest in the fields of art, museum, cultural heritage, paint, fabrics, food, plant, materials, and so on [8][9][10][11][12][13][14][15][16].…”