Light therapy goggles.
Light therapy is a relatively new approach to treating a variety of conditions, from the winter depression known as SAD (seasonal affective disorder) to eczema. It entails exposing yourself to bright, full-spectrum light that mimics the natural light of the sun. Light therapy usually involves sitting close to a light therapy box for a specified amount of time. In the case of depression, the goal is to reset your internal clock and reduce melatonin levels in your brain.
Instructions
Measuring Light for Therapy
1. Turn on the light therapy box (or whatever light source you are using) and let it get up to full strength. If the light source uses fluorescent tubes, this may take up to a minute. If it uses an incandescent light bulb-such as a grow light-there is no waiting time.
2. Stand a sheet of white paper the same distance from the light as you will be when using it. Remember that the intensity of the light will be reduced in an inverse proportion to the distance from the light source, so getting this right will affect how accurate your measurement will be.
3. Hold the light meter's sensor up to the paper as closely as possible without putting it in a shadow or blocking the light source. Several companies, like the camera manufacturer KonicaMinolta still produce and sell light meters, though they are more often used for measuring light coming from street lights or illumination levels in workplaces.
4. Take a reading from the light meter. Check to see what measuring unit your light meter is reading out. Some meters measure in lux (lumens per square meter), while others use lumens, foot candles (lumens per square foot) or even candlepower. A foot candle can also be defined as the amount of light cast by a small candle measured from 12 inches away. Candlepower is a measurement of the amount of light being put out by the light source. One candlepower is equal to 12.57 lumens.
5. If what you meaure is the candlepower (CANDELA), divide by 12.57 to find the lumens. If you have documentation that gives the candlepower of the lamp you're using, multiply that by 12.57 to get the lumens at one foot away.
Depending on the type of light meter you choose, you may need to do some simple calculations to find the lux rating. If you are using a lux meter like one of the KonicaMinolta T-10 models, you will get a direct reading of the amount of light striking the surface of the paper.
Tags: light source, light meter, amount light, from light, distance from, distance from light