The clouds have settled in with the forecast seeming to cycle between “partly cloudy” and “partly sunny.” What’s the difference? It’s all psychology — unless the sun has set. Meanwhile I am trying to make sense, if there is any, of the term “full spectrum lighting.” Turns out that’s mostly psychology too, at least according to Seattle’s Lighting Design Lab. Their consumer guidance states: “The phrase ‘full-spectrum lighting’ is not scientific terminology, it is primarily a marketing term. It can mean anything you want it to, and usually does.” Typically a full-spectrum light is designed to simulate daylight with a blue color, however this actually reduces the level of light produced. Research on seasonal affective disorder (SAD) shows that the key to effective treatment is morning exposure to high levels of light. 2500 lux (lumens per square meter: lighting terms) is the recommended minimum. Four flourescent light tubes, as are used in the light boxes sold for SAD therapy, will suffice.