---Tim Vitale <[log in to unmask]> wrote:
>
> They are misleading you, or you misunderstood.  400-750 nm is the
> wavelength range of light in the visible region.  UV light is between
> 200-420 nm.  Normal glass (not pure quartz glass) cuts off UV below
> about 325 nm.  mW/lumen is an energy measurement.  Thus, you are
getting
> a measurement of the UV energy (milliwatts) per lumen of light.
>
> Converting from other units to mW/l is easy in some case and
complicated
> in others, depending if the surface area of the sensor is known.   A
> Lumen is a unit of light emitted from a point source at one
candelpower;
> 1 lumen = 0.001496 watts.  1 lumen/square meter = 1 Lux; see, you need
> the area of the sensor to convert to Lux, which are the units you
> probably know.  Generally if you compare one lamps output (in any
units)
> to another lamps output (in those same units) to use the measurements
> effectively.
>
> Timothy Vitale
> Preservation Associates
> 831-684-2731
>

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