It has been shown that with dyeings of low fastness, the visible part of the spectrum is largely responsible for fading whereas with medium and particularly, high fastness dyes, fading is mainly caused by uv light. Thus, low fastness dyes can, in general, only be protected by e.g., yellow glass. There are exceptions to these generalizations and no selection of dyeings could be regarded as fully representative. Gave results for dying of acrylic, cotton, and nylon fabric.