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E5 - IPL filters – What do the numbers mean?
IPL systems typically use a Xenon flash lamp to generate light across a wide range of wavelengths, usually 400 to 1200 nm.
To select a 'useful' range a filter is applied. These are generally 'cut off' filters which stop all wavelengths below a given value, from transmitting through.
Hence, a 650 nm will stop all the wavelength between 400 and 650 nm, while allowing only those above 650 nm through to the skin.
Below are a set of filters used in an IPL system with a white back-light to show up the colour of each filter:
420 nm filter
This is a 420 nm filter - right down at the blue end of the visible spectrum. Blue light can be used to target the porphyrins in bacteria.
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