lightfastness
Sunlight with its high UV light content has a strong decomposing effect on many materials, which can lead to a visible change in color (fading).
The extent to which the printing inks fade depends on various factors:
- Duration of sun exposure (UV exposure)
- Location
- ozone pollution
- lightfastness
- etc.
Lightfastness describes the constancy of paints, varnishes and other surfaces under prolonged lighting. The measurement of lightfastness is regulated in the standard DIN EN ISO 105-B02 and is divided into 1-8 lightfastness levels according to this standard:
| Evaluation | lightfastness | open-air duration in days* |
| lightfastness1 | very low | 5 |
| lightfastness2 | small amount | 10 |
| lightfastness3 | moderate | 20 |
| lightfastness4 | pretty good | 40 |
| lightfastness5 | good | 80 |
| lightfastness6 | very good | 160 |
| lightfastness7 | excellent | 350 |
| lightfastness8 | terrific | 700 |
|
*First noticeable color changes |
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Explanation of the duration of exposure or open-air exposure: this depends largely on the time of year (i.e. low sunlight in winter and intense sunlight in summer) and on the geographical location, ie in southern locations such as Spain, there are generally significantly more sunny days than in Austria, Germany or Nordic countries.
Depending on the product, printing technique and color tone, our printing inks have an average lightfastness of 6-7, in the worst case still a good value of 5-6.
100% lightfastness is not possible! Every printed fabric will fade to a greater or lesser extent when exposed to direct sunlight.