Measure PAR/PPFD

Measure PAR/PPFD

To optimize lighting for plant growth it is necessary to measure the light quantity as PPFD – and the best solution for this is GL Optic’s measurement equipment along with its dedicated software.

The light visible to the human eye (approx.380-780 nm) is also used by plants. This part of the electromagnetic radiation, which powers photosynthesis, is named PAR and is usually found in wavelengths from 400 to 700nm.

For plant growers, biologists and scientists the most important data in the light requirements for plants is PPFD (photosynthetic photon flux density). PPFD is a measurement of the amount of light that actually reaches a plant (the number of photosynthetically active photons that fall on a given surface each second).

However for manufacturers growing lights, PPF measurement will be also important. This evaluates the total amount of energy that is produced by a light source per second.
The ideal tool for measurements of light which stimulates plant growth is our GL Spectis 1.0 Touch which works in the PAR spectra and expresses PPFD values in μmol/m2/s and PPF in μmol/s. For the laboratory application we recommend GL Spectis 5.0 Touch which is enriched with a higher resolution and extended spectral range. Both spectrometers can also operate with a waterproof accessory GL Opti Probe 1.1.10 illuminance, which can work under water and measure the euphotic zone. The right equipment for the PPF measurements is GL Opti Sphere – available in diameter from 48 mm up to 2 m. To be able to analyze, compare and report all the data it is highly recommended to use GL Spectrosoft – laboratory grade software compatible with the GL Optic spectrometer.



  • Agriculture fish and animal lighting users
  • Scientists and testing laboratories
  • Growing lights manufacturers


  • PPFD – photosynthetic photon flux density, which covers PAR (photosynthetically active radiation; from 400 nm – 700nm)
  • PPF – photosynthetic photon flux, which covers PAR

Moreover our spectrometers can make photometric and colorimetric measurements of light sources:

  • Lumen – the luminous flux
  • CCT – correlated color temperature according to CIE standard
  • CRI – color rendering index according to CIE
  • COLOR – color coordinates according to CIE 1931 and CIE 1964
  • mWatt – radiant power Value

Build your own set using:

GL SPECTIS 1.0 Touch is a must-have in agriculture, forestry and oceanography for:

  • setting up, controlling and making more efficient farmlands
  • evaluating environments of growth for all flora
  • learning more about the photosynthetic processes of plants and bacteria
  • researching the behavior of pigments in plants
  • projecting, manufacturing and controlling growing lights

GL SPECTIS 5.0 Touch is ideal for scientists for:

  • laboratory tests
  • projecting, manufacturing and controlling growing lights (more advanced version with wide wavelength range 200-1050 nm)
  • setting up, controlling and making farmland more efficient
  • evaluating environments of growth for all flora
  • learning more about the photosynthetic processes of plants and bacteria
  • researching the behavior of pigments in plants

GL Opti Probe 1.1.10 illuminance is an accessory which:

  • can evaluate high intensity under water
  • measure light sources in PAR (works from 400 nm)
  • is waterproof and can work under water up to 1.5 nm (it is a length of fiber optic cable)

GL Opti Sphere is an instrument which:

  • can measure PPF data
  • Is available in different sizes: 48mm, 205 mm, 500 mm and 2000 mm)

The GL SPECTROSOFT software included in the package is intuitive, user-friendly, delivers results within seconds and features easy export and import functions. This is the ideal tool for a production environment and field work, as well as laboratories and can be used for various applications:

  • comparing the collected data
  • analyses in easy to interpret graphs saved reports (in editable files: Excel, PDF etc.)


Our products get along well with each other. You're not limited to one set of equipment. Choose the one that serves your needs.


The solution for optimizing lighting for plant's growth - measurements of PPF and PPFD.


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