The testing examined colour and gloss changes in copper due to the effect of solar radiation and moisture.
The colour and gloss of a Nordic Royal copper sheet was measured weekly. The sheet was aged by the use of combined daylight and moisture stress. Acidic (pH 5) sulfidic water was used for the moisture stress test of the sample. The total duration of the test was 1 000 hours. The dose of solar radiation was 1 224 kWh/m2. A product in Northern Europe will be subjected to a comparable dose of solar radiation during a time span of 16 months on average.