Seneye Products > Seneye USB device > seneye reef light meter functions > No kelvin on light readings
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    Modern lights will often produce strong colours which are way off the kelvin (K) line (the curved black line in the centre of  the CIE spectrum shown below). Any light that does not fall on the line can be classified as a colour but not a kelvin. 



    Once you are above 10k, the kelvin quickly shifts up and toward infinity with the addition of only tiny amounts of blue light. This will create a point so far off the line that we have to label it ‘not a kelvin’. Also, plant tubes high in green can pull the spectra point away from the line toward being a green colour.

    Actinic lighting does not have a kelvin; it is a blue-coloured (wavelength) lamp, and a single tube can add significant amounts of blue which will also give ‘not a kelvin'. Seneye looks at the combined light hitting an area i.e. what the plant or coral will receive. The advent of LED lights (especially high blue) has made this deviation away from a kelvin much more common.
    We hope this helps in your understanding and also helps you appreciate why we included a 3 point spectra meter on the software to help people see where their light is peaking, even when a kelvin is not present.
    We do have some info on the main website that is worth a quick read and can be reached from the links below:

    General Lighting