A uv digital photometer is a device that takes measures of intensity of light and optical characteristics of surfaces and solutions. Photometers measure: fluorescence, absorption of light, light reflection, illumination, irradiance, phosphorescence, luminescence, and scattering of light. Anciently, photometry took place using eye estimation before electric light sensitive devices came up. Historically this is how photometry took place: You compare a source that is standard with a comparative luminous instability of a source. You then place a photometer such that the standard source is equal to the luminance of the source you investigate. When the luminance drops correspondingly to the inverse square distance, you can calculate the luminous fluxes. A piece of paper that has an oil spot making the paper a little more transparent is a conventional example of a photometer. The luminance from the both sides is equal when the oil spot from either side is not visible.
Many photometers detect an intensity of light using photodiodes, photomultipliers and photo resistors. Photometers measure the light after passing via a filter or a monochromator to analyze light. Currently, we use Ultra-Violet photometers that are digital. There are optical devices that measure the absorption of light with a variety of wavelengths of solutions’ colored substances. By the use of BEER’S law, it is possible to calculate a concentration of colored matter in solutions. Absorption Photometers work in visible and ultraviolet ranges in solutions that are aqueous.
The UV photometers’ digital display shows the percentage of the ultraviolet light going through the lens; this is an accurate way of checking the transmission properties of the UV treated glass. The exposure to Ultraviolet energy may cause permanent or temporary eye injury and irritations. For maximum protection, it is advisable you wear safety glasses and avoid direct contact with the ultraviolet light source. While setting up the UV digital photometer, you connect it to a power supply and plug into a standard opening away from the direct area of the lens coloring process that is convenient to your working area. The photometer has a lens put at the back of the unit which has been dyed using Ultraviolet diamond dye. It is necessary to remove this lens before starting operations.
UV digital photometer has a calibrate knob and ON/OFF switch. You turn the switch ON and wait 14-20 minutes before taking any acute readings because the source of light can drift in color and intensity. You should not tamper with the photocell. Calibration takes place without the presence of the lens. You then put a lens over the photocell to test. The unit then displays the Ultraviolet transmission percentage. For accurate results, you perform the calibration process before a transmission measurement. You should always unplug the unit while servicing. When the meter gets dirty, wipe it using a slightly damp cloth because excess humidity affects the meter adversely.